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5,300 | Premature Ventricular Contractions and Non-sustained Ventricular Tachycardia: Association with Sudden Cardiac Death, Risk Stratification, and Management Strategies. | Premature ventricular contractions (PVCs) and non-sustained ventricular tachycardia (NSVT) are frequently encountered and a marker of electrocardiomyopathy. In some instances, they increase the risk for sustained ventricular tachycardia, ventricular fibrillation, and sudden cardiac death. While often associated with a primary cardiomyopathy, they have also been known to cause tachycardia-induced cardiomyopathy in patients without preceding structural heart disease. Medical therapy including beta-blockers and class III anti-arrhythmic agents can be effective while implantable cardiac defibrillators (ICD) are indicated in certain patients. Radiofrequency ablation (RFA) is the preferred, definitive treatment in those patients that improve with anti-arrhythmic therapy, have tachycardia-induced cardiomyopathy, or have certain subtypes of PVCs/NSVT. We present a review of PVCs and NSVT coupled with case presentations on RFA of fascicular ventricular tachycardia, left-ventricular outflow tract ventricular tachycardia, and Purkinje arrhythmia leading to polymorphic ventricular tachycardia. |
5,301 | Anatomic guidance for ablation: atrial flutter, fibrillation, and outflow tract ventricular tachycardia. | After initial documentation of excellent efficacy with radiofrequency ablation, this procedure is being performed increasingly in more complex situations and for more difficult arrhythmia. In these circumstances, an accurate knowledge of the anatomic basis for the ablation procedure will help maintain this efficacy and improve safety. In this review, we discuss the relevant anatomy for electrophysiology interventions for typical right atrial flutter, atrial fibrillation, and outflow tract ventricular tachycardia. In the pediatric population, maintaining safety is a greater challenge, and here again, knowing the neighboring and regional anatomy of the arrhythmogenic substrate for these arrhythmias may go a long way in preventing complications. |
5,302 | Interference of remote magnetic catheter navigation and ablation with implanted devices for pacing and defibrillation. | Remote magnetic catheter navigation (RMN) may facilitate catheter ablation. However, as the system uses permanent magnets, interference (INF) with devices for pacing [pacemaker (PM)], defibrillation [implantable cardioverter defibrillators (ICD)], or cardiac resynchronisation [cardiac resynchronization therapy (CRT)] may occur. We investigated the effects of the RMN system on implanted arrhythmia devices in a prospective series.</AbstractText>Prior to RMN-guided electrophysiological procedures, devices were fully interrogated and programmed to VVI 40/min with tachycardia detection off (if applicable). Periprocedural device performance was monitored by 12-lead electrocardiogram, and duration and effect of asynchronous stimulation resulting from INF were evaluated. Following the procedure, devices were again interrogated and system integrity verified. A total of 21 procedures in 18 patients with implanted devices [PM n = 12, ICD n = 3, CRT-pacemaker (P) n = 1, CRT-defibrillation (D) n = 2] were evaluated. No relevant changes in lead parameters or device programming were observed after the procedure. No INF was noted in ICD/CRT-D devices (tachycardia detection off) and in 2 PMs, whereas 10 PMs and 1 CRT-P switched to asynchronous stimulation for 1.8 ± 0.3 h (63 ± 13% of RMN duration) without clinical adverse effects. In one patient, ventricular tachycardia (VT) degenerating in ventricular fibrillation occurred, but no causal relation between INF and VT initiation could be ascertained.</AbstractText>This prospective data provide no evidence that using RMN in patients with implanted arrhythmia devices may cause persistent device dysfunction. Asynchronous PM stimulation is common without negative clinical consequences. Although a causal role of INF for the VT observed seems unlikely, risks and benefits of RMN utilization should carefully be weighed for each patient with an implanted arrhythmia device.</AbstractText> |
5,303 | Incidence of rearrest after return of spontaneous circulation in out-of-hospital cardiac arrest. | Return of spontaneous circulation (ROSC) occurs in 35.0 to 61.0% of emergency medical services (EMS)-treated out-of-hospital cardiac arrests (OHCAs); however, not all patients achieving ROSC survive to hospital arrival or discharge. Previous studies have estimated the incidence of some types of rearrest(RA) at 61.0 to 79.0%, and the electrocardiogram (ECG) waveform characteristics of prehospital RA rhythms have not been previously described.</AbstractText>We sought to determine the incidence of RA in OHCA, to classify RA events by type, and to measure the time from ROSC to RA. We also conducted a preliminary analysis of the relationship between first EMS-detected rhythms and RA, as well as the effect of RA on survival.</AbstractText>The Pittsburgh Regional Clinical Center of the National Heart, Lung, and Blood Institute (NHLBI) -sponsored Resuscitation Outcomes Consortium (ROC) provided cases from a population-based cardiac arrest surveillance program, ROC Epistry. Only OHCA cases of nontraumatic etiology with available and adequate ECG files were included. We analyzed defibrillator-monitor ECG tracings (Philips MRX), patient care reports (PCRs), and defibrillator audio recordings from EMS-treated cases of OHCA spanning the period from October 2006 to December 2008. We identified ROSC and RA through interpretation of ECG tracings and audio recordings. Rearrest events were categorized as ventricular fibrillation (VF), pulseless ventricular tachycardia (VT), asystole, and pulseless electrical activity (PEA) based on ECG waveform characteristics. Proportions of RA rhythms were stratified by first EMS rhythm and compared using Pearson's chi-square test. Logistic regression was used to test the predictive relationship between RA and survival to hospital discharge.</AbstractText>Return of spontaneous circulation occurred in 329 of 1,199 patients (27.4% [95.0% confidence interval (CI): 25.0-30.0%]) treated for cardiac arrest. Of these, 113 had ECG tracings that were available and adequate for analysis. Rearrest occurred in 41 patients (36.0% [95.0% CI: 26.0-46.0%]), with a total of 69 RA events. Survival to hospital discharge in RA cases was 23.1% (95.0% CI: 11.1-39.3%), compared with 27.8% (95.0% CI: 17.9-39.6%) in cases without RA. Counts of RA events by type were as follows: 17 VF (24.6% [95% CI: 15.2-36.5%]), 20 pulseless VT (29.0% [95.0% CI: 18.7-41.2%]), 26 PEA (37.0% [95.0% CI: 26.3-50.2%]), and six asystole (8.8% [95.0% CI: 3.3-18.0%]). Rearrest was not predictive of survival to hospital discharge; however, initial EMS rhythm was predictive of RA shockability. The overall median (interquartile range) time from ROSC to RA among all events was 3.1 (1.6-6.3) minutes.</AbstractText>In this sample, the incidence of RA was 38.0%. The most common type of RA was PEA. Shockability of first EMS rhythm was found to predict subsequent RA rhythm shockability.</AbstractText> |
5,304 | Delayed time to defibrillation after intraoperative and periprocedural cardiac arrest. | Delay in defibrillation (more than 2 min) is associated with worse survival in patients with a cardiac arrest because of ventricular fibrillation or pulseless ventricular tachycardia in intensive care units and inpatient wards.</AbstractText>We tested the relationship between delayed defibrillation and survival from intraoperative or periprocedural cardiac arrest, adjusting for baseline patient characteristics. The analysis was based on data from 865 patients who had intraoperative or periprocedural cardiac arrest caused by ventricular fibrillation or pulseless ventricular tachycardia in 259 hospitals participating in the National Registry of Cardiopulmonary Resuscitation.</AbstractText>The median time to defibrillation was less than 1 min (interquartile range, <1 to 1 min). Delays in defibrillation occurred in 119 patients (13.8%). Characteristics associated with delayed defibrillation included pulseless ventricular tachycardia and noncardiac admitting diagnosis. The association between delayed defibrillation and survival to hospital discharge differed for periprocedural and intraoperative cardiac arrests (P value for interaction = 0.003). For patients arresting outside the operating room, delayed defibrillation was associated with a lower probability of surviving to hospital discharge (31.6% vs. 62.1%, adjusted odds ratio 0.49; 95% CI 0.27, 0.88; P = 0.018). In contrast, delayed defibrillation was not associated with survival for cardiac arrests in the operating room (46.8% vs. 39.6%, adjusted odds ratio 1.23, 95% CI 0.70, 2.19, P = 0.47).</AbstractText>Delays in defibrillation occurred in one of seven cardiac arrests in the intraoperative and periprocedural arenas. Although delayed defibrillation was associated with lower rates of survival after cardiac arrests in periprocedural areas, there was no association with survival for cardiac arrests in the operating room.</AbstractText> |
5,305 | Prevalence and predictors of pulmonary hypertension in elderly patients with isolated diastolic heart failure. | Despite the growing recognition that pulmonary hypertension can develop in diastolic heart failure; its clinical significance remains poorly defined.</AbstractText>We sought to explore the prevalence and predictors of pulmonary hypertension in elderly patients with isolated diastolic heart failure.</AbstractText>We enrolled 100 consecutive elderly patients with isolated diastolic heart failure. All patients underwent transthoracic echocardiography to measure the pulmonary artery systolic pressure, diastolic function indices (mitral E peak deceleration time, isovolumetric relaxation time, early mitral annular diastolic velocity), left atrial diameter and left ventricular mass index. Pulmonary hypertension was defined as pulmonary artery systolic pressure > or = 37 mm Hg. We classified patients into two groups: one with diastolic heart failure and concomitant pulmonary hypertension, and one with diastolic heart failure but without concomitant pulmonary hypertension.</AbstractText>The mean age of the whole series was 65.4 + or - 5.4 years, 49 (49%) being female. Patients with pulmonary hypertension (20% of the whole series) were more often females, hypertensive, more likely to have atrial fibrillation, pulmonary congestion symptoms, larger left atrial diameter, lower early mitral annular diastolic velocity, lower left ventricular ejection fraction, and more likely to have mitral regurgitation (p < 0.05 for all). Multivariate logistic regression analysis identified female gender, atrial fibrillation, and early mitral annular diastolic velocity (e') as the independent predictors of the presence of pulmonary hypertension.</AbstractText>Pulmonary hypertension is fairly prevalent in elderly patients with diastolic heart failure. Female gender, atrial fibrillation, and early mitral annular diastolic velocity (e') were the independent predictors of the presence of pulmonary hypertension in this patient group.</AbstractText> |
5,306 | Exploring newer cardioprotective strategies: ω-3 fatty acids in perspective. | In the 1980s, observational retrospective studies showed an inverse relation between coronary heart disease (CHD) and consumption of fish containing fatty acids that belong to the omega (ω)-3 family. Large case-control studies and prospective intervention trials consistently showed that ω-3 fatty acids supplementation lowers fatal myocardial infarction (MI) and sudden cardiac death. By analysing the strengths of the results of individual studies and how the meta-analyses agree with them, putting together relevant backgrounds, and identifying open questions, the following findings/directions emerge. (i) Dietary and non-dietary intake of ω-3 fatty acids reduces overall mortality, mortality due to MI, and sudden death in patients with CHD; (ii) Fish oil consumption directly or indirectly affects cardiac electrophysiology. Fish oil reduces heart rate, a major risk factor for sudden death; (iii) Among patients with implantable cardioverter defibrillators, ω-3 fatty acids do not reduce the risk of ventricular tachycardia/ventricular fibrillation and may actually be pro-arrhythmic; (iv) The consumption of ω-3 fatty acids leads to a 10-33% net decrease of triglyceride levels. The effect is dose-dependent, larger in studies with higher mean baseline triglyceride levels, and consistent in different populations (healthy people, people with dyslipidaemia, diabetes, or known cardiovascular risk factors); (v) Outcomes for which a small beneficial effect ω-3 fatty acids is found include blood pressure (about 2 mmHg reduction), re-stenosis rates after coronary angioplasty (14% reduction), and exercise tolerance testing. Major experimental data provide strength (biological plausibility) for these findings, and define directions for newer clinical trials with ω-3 fatty acids. |
5,307 | Time in recurrent ventricular fibrillation and survival after out-of-hospital cardiac arrest. | Current resuscitation guidelines (2005 guidelines [G2005]) accelerate ventricular fibrillation (VF) recurrence. We investigated whether patients resuscitated under G2005 spend more time in VF and have better survival rates than patients treated under the 2000 guidelines (G2000).</AbstractText>We analyzed continuous ECG recordings of out-of-hospital cardiac arrests prospectively collected from January 2006 to January 2008. Patients treated according to G2000 (n=282) or G2005 (n=240) with VF as initial rhythm were included. We measured the total time a patient was in recurrent VF (the sum of all intervals from each onset of recurrent VF to each next successful shock) and the time a patient was in initial VF (time interval from rescuer arrival to first effective shock). The primary outcome measure was neurologically intact survival to discharge. The median time in recurrent VF was 2.7 minutes (quartile 1 to 3, 0.4 to 9.0 minutes) under G2000 versus 4.0 minutes (quartile 1 to 3, 0.2 to 11.6 minutes) under G2005 (P=0.03). Median time in initial VF was 2.7 minutes (quartile 1 to 3, 1.7 to 4.3 minutes) versus 3.9 minutes (quartile 1 to 3, 2.3 to 6.5 minutes), respectively (P<0.001). Increased time in recurrent VF was significantly associated with decreased neurologically intact survival in both G2000 use (odds ratio, 0.92; 95% confidence interval, 0.87 to 0.97; P=0.001) and G2005 use (odds ratio, 0.94; 95% confidence interval, 0.90 to 0.99; P=0.02). Neurologically intact survival decreased significantly with increasing time in initial VF under G2000 (odds ratio, 0.86; 95% confidence interval, 0.74 to 0.99; P=0.04). This observation was nonexistent in patients treated under G2005. Neurologically intact survival was 29% (82 of 282) under G2000 versus 27% (65 of 240) under G2005 (P=0.61).</AbstractText>With G2005, the time in recurrent VF remains associated with worse outcome. Studies of immediate defibrillation for recurrent VF are warranted.</AbstractText> |
5,308 | Advances in Antiarrhythmic Drug Therapy: New and Emerging Therapies. | Despite major advances in the nonpharmacologic therapy for arrhythmias in the past decades, there is still a substantial role for antiarrhythmic drugs especially in the treatment of atrial fibrillation and ventricular tachycardia, the most effective of which is amiodarone. Dronedarone has been developed by modifying the amiodarone molecule, thus retaining its multichannel blocking action while still reducing its toxicity. New potassium channel blockers such as vernakalant are currently under development for the treatment of atrial fibrillation and flutter. So-called upstream therapies such as renin-angiotension system antagonists, statins, and n-3 polyunsaturated fatty acids offer promise for the treatment of antiarrhythmia. This article reviews dronedarone, which is already approved and available; antiarrhythmic agents that are the most advanced in development; and upstream therapy for atrial fibrillation. |
5,309 | Acute Antiarrhythmic Therapy of Ventricular Tachycardia and Ventricular Fibrillation. | Ventricular arrhythmias (ventricular tachycardia and ventricular fibrillation) are often associated with underlying structural heart disease and require prompt assessment and treatment. Acute treatment involves initial hemodynamic stabilization of the patient followed by suppressive treatment with pharmacologic and nonpharmacologic approaches for reducing the risk of recurrence of ventricular arrhythmias and potential development of sudden cardiac death. This article reviews acute antiarrhythmic drug therapy for ventricular arrhythmias based on the clinical presentation. |
5,310 | Chronic Maintenance of Sinus Rhythm in Patients with Atrial Fibrillation Using Antiarrhythmic Drugs: Update 2010. | Atrial fibrillation (AF) is a growing public health concern. For most patients the treatment of AF involves antiarrhythmic drugs. Despite the widespread use of antiarrhythmic drugs for the conversion of AF and maintenance of normal sinus rhythm, their use is limited by modest efficacy, frequent intolerance, and the potential for serious ventricular proarrhythmia and organ toxicity. Better medications are urgently needed. Optimizing the way current agents are used is vital in the interim. This article discusses such issues. |
5,311 | Complex structure of electrophysiological gradients emerging during long-duration ventricular fibrillation in the canine heart. | Long-duration ventricular fibrillation (LDVF) in the globally ischemic heart is a common setting of cardiac arrest. Electrical heterogeneities during LDVF may affect outcomes of defibrillation and resuscitation. Previous studies in large mammalian hearts have investigated the role of Purkinje fibers and electrophysiological gradients between the endocardium (Endo) and epicardium (Epi). Much less is known about gradients between the right ventricle (RV) and left ventricle (LV) and within each chamber during LDVF. We studied the transmural distribution of the VF activation rate (VFR) in the RV and LV and at the junction of RV, LV, and septum (Sep) during LDVF using plunge needle electrodes in opened-chest dogs. We also used optical mapping to analyze the Epi distribution of VFR, action potential duration (APD), and diastolic interval (DI) during LDVF in the RV and LV of isolated hearts. Transmural VFR gradients developed in both the RV and LV, with a faster VFR in Endo. Concurrently, large VFR gradients developed in Epi, with the fastest VFR in the RV-Sep junction, intermediate in the RV, and slowest in the LV. Optical mapping revealed a progressively increasing VFR dispersion within both the LV and RV, with a mosaic presence of fully inexcitable areas after 4-8 min of LDVF. The transmural, interchamber, and intrachamber VFR heterogeneities were of similar magnitude. In both chambers, the inverse of VFR was highly correlated with DI, but not APD, at all time points of LDVF. We conclude that the complex VFR gradients during LDVF in the canine heart cannot be explained solely by the distribution of Purkinje fibers and are related to regional differences in the electrical depression secondary to LDVF. |
5,312 | Redo sternotomy for cardiac reoperations using peripheral heparin-bonded cardiopulmonary bypass circuits without systemic heparinization: technique and results. | Cardiac reoperations are challenging and time-consuming and incur a high incidence of perioperative complications because of injuries to cardiac structures, bleeding, and hemodynamic instability. Some centers are using extracorporeal circulation with heparinization at the time of resternotomy, but it leads to prolonged anticoagulation, platelet dysfunction, fibrinolysis, coagulopathy, and morbidity. The authors routinely perform resternotomy in complex surgery with the support of heparinless cardiopulmonary bypass with heparin-bonded circuits (HBCs). The authors describe their technique, indication, and results.</AbstractText>The femoral artery or axillary artery and femoral veins are cannulated before sternotomy, and cardiopulmonary bypass is instituted using an HBC without systemic heparinization. Systemic heparin (200-300 U/kg) is administered when all structures are isolated before aortic cross-clamping (activated coagulation time >400 seconds).</AbstractText>Between 1996 and 2008, 336 patients underwent redo sternotomy using the HBC for complex cardiac procedures, with 29 deaths (8.6% deaths within 30 days). Only 5 (1.5%) of 336 patients sustained injury to the right ventricle, aorta, bypass grafts, or ventricular fibrillation during re-entry without hemodynamic deterioration; and underwent uneventful repair and outcomes. There was no online HBC thrombosis.</AbstractText>This study shows that HBC without systemic heparinization during resternotomy can be used safely in complex redo cardiac surgery. The heart is completely decompressed during the resternotomy, allowing easy dissection, less likely injury to vital structures, and less bleeding without compromising the hemodynamics.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,313 | One single dose of histidine-tryptophan-ketoglutarate solution gives equally good myocardial protection in elective mitral valve surgery as repetitive cold blood cardioplegia: a prospective randomized study. | Histidine-tryptophan-ketoglutarate (HTK-Custodiol) cardioplegic solution is administered as one single dose for more than 2 hours of ischemia. No prospective randomized clinical study has compared the effects of HTK and cold blood cardioplegia on myocardial damage in elective mitral valve surgery. Thus, the main aim of the present study was to examine whether one single dose of cold antegrade HTK gives as good myocardial protection as repetitive antegrade cold blood cardioplegia in mitral valve surgery.</AbstractText>Eighty consecutive patients undergoing elective isolated mitral valve surgery for mitral regurgitation, with or without ablation for atrial fibrillation, were included in the study and randomized to HTK or blood cardioplegia. Markers of myocardial injury (troponin-T and creatine kinase MB) were analyzed at baseline and 7 hours, 1 day, 2 days, and 3 days after surgery.</AbstractText>No significant difference in creatine kinase MB and troponin-T between HTK and blood cardioplegia groups was found at any time point. There was a significant correlation between ischemic time and markers of myocardial injury in the HTK group only and significantly more spontaneous ventricular fibrillation after release of crossclamping in the HTK group.</AbstractText>One single dose of antegrade cold HTK cardioplegic solution in elective mitral valve surgery protects the myocardium equally well as repetitive antegrade cold blood cardioplegia.</AbstractText>Copyright © 2011 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,314 | Optimization of Doppler echocardiographic velocity measurements using an automatic contour detection method. | Intra- and interobserver variability in Doppler echocardiographic velocity measurements (DEVM) is a significant issue. Indeed, imprecisions of DEVM can lead to diagnostic errors, particularly in the quantification of the severity of heart valve dysfunctions. To reduce the variability and rapidity of DEVM, we have developed an automatic method of Doppler velocity wave contour detection, based on active contour models. To validate our new method, results obtained with this method were compared with those obtained manually by two experienced echocardiographers on Doppler echocardiographic images of left ventricular outflow tract and transvalvular flow velocity signals recorded in 30 patients with aortic or mitral stenosis, 20 with normal sinus rhythm and 10 with atrial fibrillation. We focused on the three essential variables that are measured routinely using Doppler echocardiography in the clinical setting: the maximum velocity (Vmax), the mean velocity (Vmean) and the velocity-time integral (VTI). Comparison between the two methods has shown a very good agreement. A small bias value was found between the two methods (between -3.9% and 0.5% for Vmax, between -4.6% and -1.4% for Vmean and between -3.6% and 4.4% for VTI). Moreover, the computation time was short, approximately 5 s. This new method applied to DEVM could, therefore, provide a useful tool to eliminate the intra- and interobserver variabilities associated with DEVM and thereby to improve the accuracy of the diagnosis of cardiovascular disease. This automatic method could also allow the echocardiographer to realize these measurements within a much shorter period of time compared with the standard manual tracing method. From a practical point of view, the model developed can be easily implemented in a standard echocardiographic system. |
5,315 | Predicting cardiotoxicity propensity of the novel iodinated contrast medium GE-145: Ventricular fibrillation during left coronary arteriography in pigs. | Severe side effects caused by iodinated radiographic contrast media (CM) are rare, but can occur in high risk patients and during percutaneous coronary intervention. To minimize this risk a new nonionic CM with low inherent osmolality has been designed, giving room for a relatively high concentration of favorable electrolytes in the isotonic formulation.</AbstractText>To test a new radiographic CM (GE-145) in a pig model of cardiotoxicity by comparing its ventricular fibrillation (VF) propensity and hemodynamic effects to that of iodixanol.</AbstractText>Test agents were injected into the left anterior descending coronary artery (LAD) of pigs through an inflated balloon catheter (injection volume 25 ml, injection rate 0.4 ml/s, maximum injection time 62.5 s). Series 1: GE-145 (338 mg I/ml) + 45 mM NaCl and iodixanol (321 mg I/ml) + 19 mM NaCl were injected in five pigs. Series 2: GE-145 (320 mg I/ml) + 45 mM NaCl + 0.1, 0.3, or 0.7 mM CaCl₂ and iodixanol (320 mg I/ml) + 19 mM NaCl + 0.3 mM CaC₂ (Visipaque) were injected in six pigs.</AbstractText>Iodixanol + NaCl caused VF in 6 of 13 injections (46%) after 60.3±7.5 s (mean ± SD). GE-145 + NaCl did not cause any VF in 13 injections (0%) (P<0.05). Iodixanol + 19 mM NaCl + 0.3 mM CaCl₂ caused VF in 9 of 9 injections (100%) after 61±4 s. GE-145 + 45 mM NaCl + 0.1, 0.3, or 0.7 mM CaCl₂ did not cause any VF during or after 9 injections of each agent (0%) (P<0.05). The least hemodynamic effects were seen with GE-145 + 45 mM NaCl + 0.7 mM CaCl₂.</AbstractText>In this model of direct administration of CM into the LAD of anesthetized pigs, the tested GE-145 formulations had a significantly lower propensity to induce VF than iodixanol with electrolytes. Favorable hemodynamic properties of GE-145 can be achieved by optimizing concentrations of sodium and calcium.</AbstractText> |
5,316 | Evaluation of left ventricular dyssynchrony using combined pulsed wave and tissue Doppler imaging. | The combination of pulsed wave (PW) and tissue Doppler imaging (TDI) has been proposed as a new method to assess left ventricular (LV) mechanical dyssynchrony (LVMD), but results have not been validated. We investigated the correlation of a combination of PW and TDI with a positive response to cardiac resynchronization therapy (CRT).</AbstractText>We studied 108 consecutive patients who received CRT. Patients with atrial fibrillation were excluded. The time difference (T(PW-TDI)) between onset of QRS to the end of LV ejection by PW (T(PW)) and onset of QRS to the end of the systolic wave in LV basal segments with greatest delay by TDI (T(TDI)) was measured before CRT and during short-term and long-term follow-up.</AbstractText>The T(PW-TDI) interval before CRT was 74 ±48 ms. Intra-observer variabilities for T(PW) and T(TDI) were 1.5 ±0.24% and 1 ±0.17%. Inter-observer variabilities for T(PW) and T(TDI) were 1 ±0.36% and 1 ±0.64%, respectively. T(PW-TDI) > 50 ms was defined as the cutoff value for diagnosis of LVMD by receiver operating curve (ROC) analysis. During follow-up of 15 ±11 months, the sensitivity and specificity of TP(PW-TDI) to predict a positive response to CRT were 98% and 82%, respectively. The area under the ROC curve was 0.92. There was a significant agreement between LVMD determined by T(PW-TDI) and the positive response to CRT (κ=0.80).</AbstractText>Left vertricular dyssynchrony detected by the method combining PW and TDI demonstrated a high reproducibility, sensitivity, specificity and agreement with a positive response to CRT.</AbstractText> |
5,317 | Role of ambulance response times in the survival of patients with out-of-hospital cardiac arrest. | To evaluate the role of ambulance response times in improving survival for out-of-hospital cardiac arrest (OHCA).</AbstractText>OHCAs were identified by sampling consecutive life-threatening category A emergency ambulance calls on an annual basis for the 5 years 1996/7-2000/1 from four ambulance services in England. From these, all calls where an ambulance arrived at the scene and treated or transported a patient were included in the study. These cohorts of patients were followed up to discharge from hospital.</AbstractText>Overall, 30 (2.6%) of the 1161 patients with cardiac arrest survived to hospital discharge. If the patient arrested while the paramedics were on scene, survival to hospital discharge was 14%. The most important predictive factors for survival were response time, initial presenting heart rhythm in ventricular fibrillation and whether the arrest was witnessed. The estimated effect of a 1&emsp14;min reduction in response time was to improve the odds of survival by 24% (95% CI 4% to 48%). The costs of reducing response times across the board by 1 at the time of this study were estimated at around £54 million.</AbstractText>The arrival of a crew prior to OHCA means that the chance of surviving the arrest increases sevenfold. Overall it is possible that rapid response to patients in immediate risk of arrest may be at least as beneficial as rapid response to those who have arrested. Concentrating resources on reducing response times across the board to improve survival for those patients already in arrest is unlikely to be a cost-effective option to the U.K. National Health Service.</AbstractText> |
5,318 | Pericardial fat is independently associated with human atrial fibrillation. | The purpose of this study was to investigate the association between atrial fibrillation (AF) and pericardial fat.</AbstractText>Pericardial fat is visceral adipose tissue that possesses inflammatory properties. Inflammation and obesity are associated with AF, but the relationship between AF and pericardial fat is unknown.</AbstractText>Pericardial fat volume was measured using computed tomography in 273 patients: 76 patients in sinus rhythm, 126 patients with paroxysmal AF, and 71 patients with persistent AF.</AbstractText>Patients with AF had significantly more pericardial fat compared with patients in sinus rhythm (101.6 +/- 44.1 ml vs. 76.1 +/- 36.3 ml, p < 0.001). Pericardial fat volume was significantly larger in paroxysmal AF compared with the sinus rhythm group (93.9 +/- 39.1 ml vs. 76.1 +/- 36.3 ml, p = 0.02). Persistent AF patients had a significantly larger pericardial fat volume compared with paroxysmal AF (115.4 +/- 49.3 ml vs. 93.9 +/- 39.1 ml, p = 0.001). Pericardial fat volume was associated with paroxysmal AF (odds ratio: 1.11; 95% confidence interval: 1.01 to 1.23, p = 0.04) and persistent AF (odds ratio: 1.18, 95% confidence interval: 1.05 to 1.33, p = 0.004), and this association was completely independent of age, hypertension, sex, left atrial enlargement, valvular heart disease, left ventricular ejection fraction, diabetes mellitus, and body mass index.</AbstractText>Pericardial fat volume is highly associated with paroxysmal and persistent AF independent of traditional risk factors including left atrial enlargement. Whether pericardial fat plays a role in the pathogenesis of AF requires future investigation.</AbstractText>Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,319 | Prevalence and predictors of off-label use of cardiac resynchronization therapy in patients enrolled in the National Cardiovascular Data Registry Implantable Cardiac-Defibrillator Registry. | The purpose of the study was to define the extent and nature of cardiac resynchronization therapy (CRT) device usage outside consensus guidelines using national data.</AbstractText>Recent literature has shown that the application of CRT in clinical practice frequently does not adhere to evidence-based consensus guidelines. Factors underlying these practices have not been fully explored.</AbstractText>From the National Cardiovascular Data Registry's Implantable Cardiac-Defibrillator Registry, we defined a cohort of 45,392 cardiac resynchronization therapy-defibrillator (CRT-D) implants between January 2006 and June 2008 with a primary prevention indication. We defined "off-label" implants as those in which the ejection fraction was >35%, the New York Heart Association functional class was below III, or the QRS interval duration was <120 ms in the absence of a documented need for ventricular pacing. The relationships between patient, implanting physician, and hospital characteristics with off-label use were explored with multivariable hierarchical logistic regression models.</AbstractText>Overall, 23.7% of devices were placed without meeting all 3 implant criteria, most often due to New York Heart Association functional class below III (13.1% of implants) or QRS interval duration <120 ms (12.0%). Atrial fibrillation/flutter, previous percutaneous coronary intervention, and the performance of an electrophysiology study before implant were independently associated with increased odds of off-label use, whereas diabetes mellitus, increasing age, and female sex were associated with decreased odds. Physician training and insurance payer were weakly associated with the likelihood of off-label use.</AbstractText>Nearly 1 in 4 patients receiving CRT devices in the study time frame did not meet guideline-based indications. Given the evolving evidence base supporting the use of CRT, these practices require careful scrutiny.</AbstractText>Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,320 | Dronedarone: a new antiarrhythmic agent. | Dronedarone is an antiarrhythmic agent recently approved by the United States Food and Drug Administration for the reduction of cardiovascular-related hospitalizations in patients with paroxysmal or persistent atrial fibrillation or atrial flutter. The drug is a derivative of amiodarone and has been modified to reduce the organ toxicities frequently encountered with amiodarone. Dronedarone exerts its antiarrhythmic effects through multichannel blockade of the sodium, potassium, and calcium channels and also possesses antiadrenergic activity, thereby exhibiting pharmacologic effects of all four Vaughan Williams classes of antiarrhythmics. The efficacy of dronedarone for the maintenance of sinus rhythm, ventricular rate control, and reduction in cardiovascular-related hospitalizations has been demonstrated in several randomized, placebo-controlled trials. Although a high rate of gastrointestinal events (e.g., nausea, vomiting, and diarrhea) has been associated with dronedarone, more serious adverse events such as thyroid, liver, or pulmonary toxicities have not been observed. Because of a possible increase in mortality, dronedarone should be avoided in patients with New York Heart Association class IV or II-III heart failure with a recent decompensation. Given the efficacy and safety data currently available, dronedarone represents a reasonable alternative for maintenance of sinus rhythm in appropriately selected patients. |
5,321 | Defibrillation and resuscitation in a piglet model of pediatric ventricular fibrillation following AHA 2005 guidelines. | To evaluate the efficacy and safety of defibrillation on children according to AHA 2005 recommendations</AbstractText>Pig resembles human in the chest configuration, anatomy and physiology of the cardiovascular and pulmonary systems. Piglets weighing 7.0 Kg ± 1.4kg, 14.0kg ± 2.8kg, 25.0kg ± 5.0kg respectively, which represented children 1 to 8 yr old were induced ventricular fibrillation (VF). An adult biphasic AED was used in conjunction with pediatric attenuating electrodes which could deliver 50-J shock for 2 min and two min of cardiopulmonary resuscitation (CPR) immediately followed it. If VF did not reverse, 70-J shock combined with CPR was used, and the protocol was repeated five times. If an organized cardiac rhythm with mean aortic pressure more than 60 mmHg persisted for an interval of 5 minutes, the animal was regarded as successfully resuscitated. If the AED recognized a "non-shockable" rhythm, CPR was also performed immediately for 2 min. The same resuscitation program was exercised on piglets of manual defibrillator group. Neurologic alertness score, hemodynamic and myocardial functions were evaluated, autopsy was routinely performed to document possible injuries.</AbstractText>In the AED group, 14 out of 15 animals, were successfully resuscitated, among them 11 piglets were resuscitated by 50-J defibrillation combined with cardiopulmonary resuscitation, and other three recovered to normal by 1 or 2 times of 70-J shocks and CPR. All animals in manual defibrillator group were successfully resuscitated by 50-J shocks and CPR. Left ventricular ejection fraction and fractional area change were reduced significantly during 3-4 hr post-resuscitation (P<0.05) and returned to baseline ranges at the end of 72 hr. There was no evidence of myocardial and pulmonary damage during autopsy, and neurologic recovery was also normal. Data of blood gas analysis, blood electrolytes and myocardial enzymes does not show any statistically significant difference (P> 0.05) in the groups. 50 J biphasic dose defibrillation combined with effective CPR, successfully terminated VF without adverse effects on myocardial function and survival in a piglet defibrillation model for young children 1 to 8 yr of age.</AbstractText>The new guidelines recommendation that one shock immediately followed by CPR is reasonable. Adults AED combined with pediatric electrodes is feasible to the diagnosis and treatment of pediatric VF model. But the user should not rely too much on AED's "automatic" function, but should accumulate and integrate his experience with AED technology.</AbstractText> |
5,322 | Takotsubo cardiomyopathy presenting as postoperative atrial fibrillation. | Takotsubo cardiomyopathy (TC) is a condition which was first acknowledged in Japan and is characterized by a reversible systolic dysfunction of the apical or mid segments of the left ventricle. Typically affecting women in the post-menopausal population, it is triggered by intense emotional, physical or medical stress. Also known as apical ballooning syndrome or stress cardiomyopathy, TC derives its name from the left ventricular angiographic appearance of a 'Takotsubo', literally translated as an 'octopus fishing trap' in Japanese. Patients often describe chest pain, have ischemic electrocardiogram (ECG) changes and positive cardiac enzymes mimicking an acute coronary syndrome. Obstructive coronary artery disease is excluded with prompt cardiac catheterization. We present the case of a 78-year-old lady, post gynecological surgery, presenting with palpitations and ECG confirming fast atrial fibrillation. Despite spontaneous cardioversion, she went on to develop ECG changes and cardiac enzyme elevations suggestive of an acute myocardial infarction. Cardiac catheterization was performed and confirmed the diagnosis of TC. It highlights an atypical presentation of TC, which can present initially as an arrhythmia in the postoperative phase as a consequence of the supraphysiological effects of elevated circulating plasma catecholamines. It reiterates the importance of prompt diagnosis and treatment to prevent cardiac decompensation in a condition poorly understood. |
5,323 | Automated external defibrillation by first-responders. | This review examines whether the use of automated external defibrillators by first-responders improves the survival of adults who suffer cardiopulmonary arrest. We also examined the risks associated with these devices, based on a review of the literature using the standard Prescrire methodology. Automated external defibrillators detect ventricular fibrillation with almost perfect sensitivity and specificity. Several studies showed that the use of automated external defibrillators by trained first-responders is associated with increased survival among patients who suffer out-of-hospital cardiac arrest in public places. A retrospective study suggests that installing automated external defibrillators in public places would only allow about one-fifth of all victims of cardiac arrest to be treated; this would increase the average survival rate after cardiac arrest from about 5% to 6.5%. The main risks associated with these devices are burns to the patient's skin at the electrode contact points, and inappropriate shock to the user--a rare occurrence. Interactions between automated external defibrillators and implantable defibrillators have been described. Drug delivery patches on the patient's chest can prevent electrode-skin contact and may block delivery of the electric discharge. In the United States, about 1 in 5 functioned over a 10-year period, mainly due to electrical or software problems. In summary, automated external defibrillators have a favourable risk-benefit balance, at least in trained hands. Specific training helps first-responders to act purposefully and without delay, and to implement the chain of survival until medical help arrives. |
5,324 | Survey of the use of therapeutic hypothermia post cardiac arrest. | Therapeutic hypothermia improves neurological outcome in adults after ventricular fibrillation cardiac arrest and neonates with hypoxic ischaemic encephalopathy. There is currently no clinical research to support its use in the paediatric population. This survey aims to ascertain current practice in the UK, and attitudes and opinions to guide the feasibility of a UK multicentre, randomised, controlled trial of therapeutic hypothermia after cardiac arrest in children (The Cold-PACK Post Arrest Cooling in Kids study).</AbstractText>Anonymous survey of UK paediatric intensive care consultants (n=149).</AbstractText>A total of 113 (76%) of 149 surveys were returned; 65% responded that they do not know if therapeutic hypothermia improves survival after cardiac arrest. Despite this, 48% 'always' or 'often' use therapeutic hypothermia after return of spontaneous circulation following cardiac arrest in children. Among those who never use therapeutic hypothermia (33%) the commonest explanation given was 'not enough research evidence' (91%). With respect to the dose of therapeutic hypothermia the median duration of cooling used is 24-48 h (range 4-72 h) and median target temperature 34°C to 35°C (range 32°C to 37°C); 68% target a temperature range higher than that applied in the published adult and neonatal studies (33±1°C). There was strong support for a trial of therapeutic hypothermia being ethical (89%) and using deferred consent (85%).</AbstractText>Wide variation in UK practice in the use of therapeutic hypothermia and a state of clinical equipoise is demonstrated by this survey, which shows important support for UK multicentre collaboration in a future trial of therapeutic hypothermia after cardiac arrest.</AbstractText> |
5,325 | Sleep disordered breathing and arrhythmia burden in pacemaker recipients. | Sleep disordered breathing (SDB), a common condition among patients with permanent pacemaker (PM), is associated with greater incidence of cardiac arrhythmias. Scarce availability of sleep laboratories and the high costs of nocturnal-attended polysomnography limit the routine screening of patients with PM for SDB. We investigated whether a novel PM that utilizes variations in transthoracic impedance to record the fluctuations in breathing pattern and minute ventilation could be used to screen patients for SDB.</AbstractText>Twenty patients who underwent dual-chamber PM implantation were studied. The Talent 3 DR PM (SORIN Group Italy S.r.l., Milan, Italy) calculates apnea-hypopnea index (AHI) by computing minute ventilation signal derived from transthoracic impedance measurements. Within a month after PM implantation, an in-home respiratory monitoring was performed to evaluate the accuracy of PM-derived AHI. Patients were followed for mean ± standard deviation, 487 ± 166 days. The PM was checked at each follow-up visit to retrieve the information about recurrent arrhythmias.</AbstractText>Eleven patients were diagnosed with SDB by an in-home respiratory monitoring. An AHI derived from an in-home respiratory monitoring was similar to pacemaker-derived AHI (27 ± 14 vs 16 ± 13 events/hour, P = 0.15). The cumulative incidence of cardiac arrhythmias, including atrial fibrillation, extrasystolic beats, sustained and nonsustained ventricular tachycardia, and supraventricular tachycardia was similar in patients with and without SDB.</AbstractText>SDB is highly prevalent in patients with permanent pacemaker. Screening for SDB with Talent 3 DR PM may facilitate diagnosis and treatment of SDB.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,326 | ICD defibrillation failure solved in an unusual fashion. | An implantable cardioverter defibrillator (ICD) is designed to sense life-threatening ventricular arrhythmias and terminate them, either by rapid pacing or by delivering an electrical shock. Nowadays it is a proven therapy for both primary and secondary prevention of sudden cardiac death. The typical configuration of an ICD consists of a right ventricular sensing/defibrillator lead with two coils (one distal, located in the right ventricle, and one proximal, located at the superior vena cava-right atrium junction) and an active can, the so-called "ventricular triad". Although effective in the vast majority of patients, it could be argued that this is not the most rational arrangement in electrical terms, since the main shock vector is anteriorly displaced in relation to the greater portion of the left ventricular mass. We describe a case of an ICD defibrillation failure that was solved by placing an additional defibrillator lead in a tributary of the coronary sinus. |
5,327 | Association between clinical examination and outcome after cardiac arrest. | Neurologic prognostication after cardiac arrest relies on clinical examination findings derived before the advent of therapeutic hypothermia (TH). We measured the association between clinical examination findings at hospital arrival, 24, and 72 h after cardiac arrest in a modern intensive care unit setting.</AbstractText>Between 1/1/2005 and 3/31/2009, hospital charts were reviewed in 272 subjects for neurologic examination findings (Glasgow Coma Score--motor examination, pupil response, corneal response) at hospital arrival, 24, and 72 h following cardiac arrest. Primary outcome was survival to hospital discharge. Secondary outcome was "good outcome," defined as discharge to home or acute rehabilitation facility.</AbstractText>Mean age was 61 years; 155 (57%) were male. Most were treated with TH (N=161; 59%) and 100 subjects (37%) were in ventricular fibrillation/ventricular tachycardia. Out-of-hospital cardiac arrest was common (N=169; 62%). Ninety-one (33%) survived, with 54 (20%) experiencing a good outcome. In subjects with a GCS Motor score < or = 3 at 24 and 72 h survival was 17% (13/76; 95% CI 7.9-26.2%) and 20% (6/27; 95% CI 6.3-33.6%), respectively. Subjects with a GCS Motor score < or = 2 at 24 and 72 h survived in 14% (9/66; 95% CI 4.6-22.6%) and 18% (6/33; 95% CI 3.5-32.8%), respectively. Absent pupil reactivity on arrival did not exclude survival (7/65; 11%; 95% CI 2.4-19%). A lack of pupil reactivity or corneal response at 72 h was associated with death (pupil: 0/17; 95% CI 0, 2.9%; corneal: 0/21; 95% CI 0, 2.4%).</AbstractText>GCS Motor score < or = 3 or < or = 2 at 24 or 72 h following cardiac arrest does not exclude survival or good outcome. However, absent pupil or corneal response at 72 h appears to exclude survival and good outcome.</AbstractText>Copyright 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,328 | Biphasic DC shock cardioverting doses for paediatric atrial dysrhythmias. | To determine cardioversion doses of biphasic DC shock for paediatric atrial dysrhythmias.</AbstractText>Prospective recording of energy, pre-shock and post-shock rhythms.</AbstractText>Paediatric hospital.</AbstractText>Shockable atrial dysrhythmias.</AbstractText>Forty episodes of atrial dysrhythmias among 25 children (mean age 6.8+/-7.1 years, mean weight 28.2+/-28.5 kg) were treated with external shock. The first shock converted the dysrhythmia to sinus rhythm in 25 episodes. Cardioversion occurred in 2 of 8 (25%) episodes with a dose of <0.5 J/kg, 14 of 16 (88%) with a dose of 0.5-1.0 J/kg and 9 of 16 (56%) with a dose of >1.0 J/kg (p=0.01, Fisher's exact test). Ten of 15 initially non-responsive episodes were cardioverted with additional shocks at 1.1+/-0.6 J/kg (range 0.5-2.1 J/kg). Of the remaining 5 unresponsive episodes, 2 of ventricular fibrillation (induced by unsynchronized shock) were successfully defibrillated, and 3 were managed with cardiopulmonary bypass. Among 11 additional children (mean age 4.3+/-6.8 years, mean weight 18.1+/-22.0 kg), 18 episodes of atrial dysrhythmias were treated with internal shock which successfully cardioverted all episodes with one or more shocks at 0.4+/-0.2 J/kg.</AbstractText>In rounded doses, recommended initial external cardioversion doses are 0.5-1.0 J/kg and subsequently up to 2 J/kg, internal cardioversion doses are 0.5 J/kg.</AbstractText>Copyright 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,329 | Low risk of major complications associated with pulmonary vein antral isolation for atrial fibrillation: results of 500 consecutive ablation procedures in patients with low prevalence of structural heart disease from a single center. | To report the major complication rate associated with pulmonary vein antral isolation (PVAI) in a consecutive series of 500 patients from a single center.</AbstractText>Catheter ablation for atrial fibrillation (AF) is an established procedure for refractory AF. However, the risk of major complications has been reported to range from 3.9% to 4.5% and continues to represent a cause for concern. We hypothesized that these studies may have overestimated the rate of major complications associated with PVAI in patients with a low prevalence of structural heart disease (SHD).</AbstractText>Data were prospectively collected from 500 consecutive AF ablation procedures on 424 patients (mean age 55 ± 11 years, 79% men, paroxysmal AF-80% and persistent AF-20%, CHADS₂ scores of 0, 1, 2, 3 present in 64%, 28%, 7%, 1%, respectively), performed between July 2006 and September 2009. All procedures were performed under general anesthesia with intraoperative transesophageal echo. PVAI was performed using a nonfluoroscopic mapping system with an endpoint of PV isolation. Adjunctive left atrial ablation was performed in 21% of patients only. Major complications were defined from a compilation of those reported in 5 prior studies reporting complications.</AbstractText>In 500 procedures, there were no instances of death, stroke/TIA, cardiac tamponade, atrioesophageal fistula, or PV stenosis. Major complications occurred in 4 procedures (0.8%): esophageal hematoma (TEE probe)--2; pharyngeal trauma--1; and retroperitoneal hematoma-1.</AbstractText>AF ablation can be performed safely in young patients without structural heart disease with a low risk (<1%) of major complications when using a strategy of PVAI.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,330 | High concentrations of B-type natriuretic peptide and left ventricular diastolic dysfunction in patients with paroxysmal/persistent atrial fibrillation as possible markers of conversion into permanent form of arrhythmia: 1-year prospective evaluation. | Atrial fibrillation (AF) may cause electrical and structural atrial remodelling, leading to progression from paroxysmal to permanent form of arrhythmia. Predictors of such a transition have not yet been well established.</AbstractText>To assess the role of B-type natriuretic peptide (BNP) and left ventricular (LV) diastolic impairment in prediction of progression from paroxysmal/persistent AF to permanent AF.</AbstractText>The study group consisted of 154 patients (84 males, mean age 65.8 +/- 10 years) with paroxysmal (51%) or persistent (49%) AF and normal LV systolic function. All patients had BNP level and echocardiographic parameters of diastolic LV dysfunction measured at baseline and after one-year follow up.</AbstractText>After one-year follow-up, 15 (9.5%) patients developed permanent AF. These patients had significantly higher baseline and one-year BNP values than the remaining patients (96.0 v. 41 pg/mL, p < 0.005, and 151.1 v. 32.5 pg/mL, p < 0.0001, respectively). Also echocardiographic indices of LV diastolic dysfunction were abnormal in patients who developed permanent AF. Stepwise logistic regression analysis revealed that baseline BNP level had independent prognostic value in predicting permanent AF development (OR 1.06, CI 1.01-1.12, p < 0.0162). The area under ROC curve was 0.787.</AbstractText>Patient with normal systolic LV function and paroxysmal or persistent AF are likely to progress into permanent AF when they have increased BNP levels and echocardiographic signs of LV diastolic dysfunction.</AbstractText> |
5,331 | Vernakalant, a mixed sodium and potassium ion channel antagonist that blocks K(v)1.5 channels, for the potential treatment of atrial fibrillation. | Despite being the most common arrhythmia currently treated by cardiologists, safe and effective treatments for atrial fibrillation (AF) remain elusive. To address this issue, Astellas Pharma Inc, Merck & Co Inc and Cardiome Pharma Corp are developing vernakalant (RSD-1235), a drug which dose-dependently inhibits sodium channels and several potassium repolarizing currents. Of particular note, vernakalant inhibits I(Kur) (K(v)1.5), a current that is more predominant in atrial than in ventricular tissue. Consistent with this observation, vernakalant produced increases in atrial refractory period with minimal actions on QTc interval or ventricular refractory period in both humans and animals. Intravenous vernakalant terminated recent-onset AF in several animal models, and also in patients with short-duration AF or AF following cardiac surgery enrolled in phase II and III clinical trials. Vernakalant was well tolerated and adverse reactions were transient and mild. Thus, vernakalant holds considerable promise for the treatment of recent-onset AF; however, given its relatively short half-life, continuous dosing may be required in order to maintain sinus rhythm following conversion from AF. The efficacy and safety of vernakalant for the long-term management of AF remains to be determined. Phase III clinical trials with intravenous vernakalant are ongoing, and phase II clinical trials are also being conducted with an oral formulation intended for chronic use. |
5,332 | Clinical predictors of preserved left ventricular ejection fraction in decompensated heart failure. | Identification and clinical impact of preserved left ventricular ejection fraction (LVEF) on in-hospital outcomes in patients with acute decompensated heart failure (HF) remain poorly defined.</AbstractText>To describe clinical predictors and in-hospital outcomes of acute decompensated HF patients and preserved LVEF, and to develop a clinically-based predictive rule based on data acquired on admission.</AbstractText>Consecutive admissions for HF (n=721) at a tertiary care hospital were followed up to discharge or death. More than 80 clinical variables were evaluated to identify predictors of preserved LVEF upon admission.</AbstractText>Preserved LVEF (>50%) was identified in 224 (31%) hospitalizations. Clinical predictors of preserved LVEF were age > 70 years old (p=0.04), female gender (p<0.001), non-ischemic etiology (p<0.001), atrial fibrillation or flutter (p=0.001), anemia (p=0.001), pulse pressure > 45 mmHg (p<0.01) and absence of EKG conduction abnormalities (p<0.001). A clinical score based on these variables was accurate to predict preserved LVEF upon hospital admission (area under ROC curve of 0.76). No significant differences were observed on in-hospital mortality or clinical complications according to quintiles of LVEF.</AbstractText>Preserved LVEF is a prevalent and morbid condition among hospitalized HF patients. Simple clinical data obtained on admission might be useful for predicting preserved LVEF.</AbstractText> |
5,333 | Amiodarone for the treatment and prevention of ventricular fibrillation and ventricular tachycardia. | Amiodarone has emerged as the leading antiarrhythmic therapy for termination and prevention of ventricular arrhythmia in different clinical settings because of its proven efficacy and safety. In patients with shock refractory out-of-hospital cardiac arrest and hemodynamically destabilizing ventricular arrhythmia, amiodarone is the most effective drug available to assist in resuscitation. Although the superiority of the transvenous implantable cardioverter defibrillator (ICD) over amiodarone has been well established in the preventive treatment of patients at high risk of life-threatening ventricular arrhythmias, amiodarone (if used with a beta-blocker) is the most effective antiarrhythmic drug to prevent ICD shocks and treat electrical storm. Both the pharmacokinetics and the electrophysiologic profile of amiodarone are complex, and its optimal and safe use requires careful patient surveillance with respect to potential adverse effects. |
5,334 | Dronedarone in patients with atrial fibrillation. | Dronedarone is a recently developed new class III antiarrhythmic drug which possesses electrophysiological properties of all four Vaughan-Williams classes. An important difference with amiodarone is that it does not contain an iodine component and therefore lacks the iodine-related adverse effects. Based on currently available data, dronedarone can not be recommended as first-line therapy for either rhythm or rate control. We recommend to initiate rhythm or rate control with drugs as indicated in the 2006 guidelines of the ESC and other organisations. As amiodarone, dronedarone can be given to patients for whom standard drug therapy is not effective, or limited by (severe) side effects, although it is less effective than amiodarone. Nevertheless, it may be considered to give dronedarone initially to patients who would otherwise have received amiodarone, since the latter has more severe side effects than the former drug. The daily dosage of dronedarone is oral administration, 400 mg twice daily. Dronedarone is contraindicated in patients with impaired left ventricular function (NYHA class III/IV) and haemodynamic instability. (Neth Heart J 2010;18:370-3.). |
5,335 | Isolated left ventricular pacing results in worse long-term clinical outcome when compared with biventricular pacing: a single-centre randomized study. | The objective of this study was to compare long-term clinical effects of biventricular pacing with isolated left ventricular pacing.</AbstractText>Forty consecutive patients with idiopathic dilated cardiomyopathy and indication for cardiac resynchronization therapy were randomized to biventricular or isolated left ventricular pacing. Clinical and echocardiographic parameters were studied regularly prior to implantation and during 1 year of follow-up. Patients with atrial fibrillation were excluded from the study. A retrospective cross-sectional outcome analysis was performed 4 years after the beginning of the study. Biventricular pacing was associated with more pronounced clinical and echocardiographic benefit compared with left ventricular pacing. Biventricular pacing was associated with significantly more distinct reverse remodelling. Left ventricular ejection fraction improved by 12.5 per cent-points (95% CI 7.3-17.7) compared with 5.1 per cent-points (95% CI 1.1-9.2) (P = 0.01) and left ventricular end-diastolic diameter decreased by 8.69 mm (95% CI 5.2-12.2) compared with 5.1 mm (95% CI 1.5-8.7) (P = 0.05) in the biventricular and left-ventricular pacing group, respectively. Semi-quantitative summarization of response points revealed a greater benefit in the biventricular vs. left ventricular pacing group [mean sum of response points 3.25 (95% CI 2.62-3.88) vs. 2.35 (95% CI 1.74-2.96), respectively, P = 0.06]. After 3 years of follow-up, there was no cardiovascular death in the biventricular pacing group compared with three cardiovascular deaths in the left ventricular pacing group.</AbstractText>In patients with idiopathic dilated cardiomyopathy, biventricular pacing is associated with significantly more pronounced benefit in clinical outcomes and reverse remodelling. A retrospective analysis after 3 years of follow-up suggests that isolated left ventricular pacing may be associated with a higher mortality rate compared with biventricular pacing.</AbstractText> |
5,336 | Defining new insight into atypical arrhythmia: a computational model of ankyrin-B syndrome. | Normal cardiac excitability depends on the coordinated activity of specific ion channels and transporters within specialized domains at the plasma membrane and sarcoplasmic reticulum. Ion channel dysfunction due to congenital or acquired defects has been linked to human cardiac arrhythmia. More recently, defects in ion channel-associated proteins have been associated with arrhythmia. Ankyrin-B is a multifunctional adapter protein responsible for targeting select ion channels, transporters, cytoskeletal proteins, and signaling molecules in excitable cells, including neurons, pancreatic β-cells, and cardiomyocytes. Ankyrin-B dysfunction has been linked to cardiac arrhythmia in human patients and ankyrin-B heterozygous (ankyrin-B(+/-)) mice with a phenotype characterized by sinus node dysfunction, susceptibility to ventricular arrhythmias, and sudden death ("ankyrin-B syndrome"). At the cellular level, ankyrin-B(+/-) cells have defects in the expression and membrane localization of the Na(+)/Ca(2+) exchanger and Na(+)-K(+)-ATPase, Ca(2+) overload, and frequent afterdepolarizations, which likely serve as triggers for lethal cardiac arrhythmias. Despite knowledge gathered from mouse models and human patients, the molecular mechanism responsible for cardiac arrhythmias in the setting of ankyrin-B dysfunction remains unclear. Here, we use mathematical modeling to provide new insights into the cellular pathways responsible for Ca(2+) overload and afterdepolarizations in ankyrin-B(+/-) cells. We show that the Na(+)/Ca(2+) exchanger and Na(+)-K(+)-ATPase play related, yet distinct, roles in intracellular Ca(2+) accumulation, sarcoplasmic reticulum Ca(2+) overload, and afterdepolarization generation in ankyrin-B(+/-) cells. These findings provide important insights into the molecular mechanisms underlying a human disease and are relevant for acquired human arrhythmia, where ankyrin-B dysfunction has recently been identified. |
5,337 | A clinical prediction model to estimate risk for 30-day adverse events in emergency department patients with symptomatic atrial fibrillation. | Atrial fibrillation affects more than 2 million people in the United States and accounts for nearly 1% of emergency department (ED) visits. Physicians have little information to guide risk stratification of patients with symptomatic atrial fibrillation and admit more than 65%. Our aim is to assess whether data available in the ED management of symptomatic atrial fibrillation can estimate a patient's risk of experiencing a 30-day adverse event.</AbstractText>We systematically reviewed the electronic medical records of all ED patients presenting with symptomatic atrial fibrillation between August 2005 and July 2008. Predefined adverse outcomes included 30-day ED return visit, unscheduled hospitalization, cardiovascular complication, or death. We performed multivariable logistic regression to identify predictors of 30-day adverse events. The model was validated with 300 bootstrap replications.</AbstractText>During the 3-year study period, 914 patients accounted for 1,228 ED visits. Eighty patients were excluded for non-atrial-fibrillation-related complaints and 2 patients had no follow-up recorded. Of 832 eligible patients, 216 (25.9%) experienced at least 1 of the 30-day adverse events. Increasing age (odds ratio [OR] 1.20 per decade; 95% confidence interval [CI] 1.06 to 1.36 per decade), complaint of dyspnea (OR 1.57; 95% CI 1.12 to 2.20), smokers (OR 2.35; 95% CI 1.47 to 3.76), inadequate ventricular rate control (OR 1.58; 95% CI 1.13 to 2.21), and patients receiving β-blockers (OR 1.44; 95% CI 1.02 to 2.04) were independently associated with higher risk for adverse events. C-index was 0.67.</AbstractText>In ED patients with symptomatic atrial fibrillation, increased age, inadequate ED ventricular rate control, dyspnea, smoking, and β-blocker treatment were associated with an increased risk of a 30-day adverse event.</AbstractText>Copyright © 2010 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,338 | Knock-in gain-of-function sodium channel mutation prolongs atrial action potentials and alters atrial vulnerability. | Patients with long QT syndrome (LQTS) are at increased risk not only for ventricular arrhythmias but also for atrial pathology including atrial fibrillation (AF). Some patients with "lone" AF carry Na(+)-channel mutations.</AbstractText>The purpose of this study was to determine the mechanisms underlying atrial pathology in LQTS.</AbstractText>In mice with a heterozygous knock-in long QT syndrome type 3 (LQT3) mutant of the cardiac Na(+) channel (ΔKPQ-SCN5A) and wild-type (WT) littermates, atrial size, function, and electrophysiologic parameters were measured in intact Langendorff-perfused hearts, and histologic analysis was performed.</AbstractText>Atrial action potential duration, effective refractory period, cycle length, and PQ interval were prolonged in ΔKPQ-SCN5A hearts (all P < .05). Flecainide (1 μM) reversed atrial action potential duration prolongation and induced postrepolarization refractoriness (P < .05). Arrhythmias were infrequent during regular rapid atrial rate in both WT and ΔKPQ-SCN5A but were inducible in 15 (38%) of 40 ΔKPQ-SCN5A and 8 (29%) of 28 WT mice upon extrastimulation. Pacing protocols generating rapid alterations in rate provoked atrial extrasystoles and arrhythmias in 6 (66%) of 9 ΔKPQ-SCN5A but in 0 (0%) of 6 WT mice (P < .05). Atrial diameter was increased by nearly 10% in ΔKPQ-SCN5A mice > 5 months old without increase in fibrotic tissue.</AbstractText>Murine hearts bearing an LQT3 mutation show abnormalities in atrial electrophysiology and subtle changes in atrial dimension, including an atrial arrhythmogenic phenotype on provocation. These results support clinical data suggesting that LQTS mutations can cause atrial pathology and arrhythmogenesis and indicate that murine sodium channel LQTS models may be useful for exploring underlying mechanisms.</AbstractText>Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,339 | Late potential at the high ventricular septal level in a patient with Brugada: possible mechanisms and clinical implications. | The Brugada syndrome (BS) accounts for approximately 20% of cases of sudden cardiac death in patients with structurally normal hearts. The electrophysiologic basis for ST-segment elevation in the precordial electrocardiogram (ECG) leads that characterize the Brugada phenotype and its strong linkage to ventricular tachycardia (VT)/ventricular fibrillation is still a subject of controversy. Electrocardiographic manifestations of the syndrome have been attributed to one of two basic mechanisms: (1) conduction delay in the right ventricular (RV) epicardial-free wall in the region of the outflow tract or (2) premature repolarization of the RV epicardial action potential secondary to loss of the action potential dome. Signal-averaged ECG recordings have demonstrated late potentials that extend beyond the QRS complex in patients with the BS, especially in the anterior wall of the RV outflow tract. The basis for these epicardial late potentials remains a subject of interest among basic and clinical electrophysiologists. Endocardial late potentials in BS are even less well understood. We present a case of a patient with Brugada syndrome with a distinct endocardial late potential in the high ventricular septum coinciding with the ST-segment elevation. We discuss the possible mechanisms for this intracardiac finding and its clinical significance. We also review the effect of isoproterenol infusion on both the late potential and the surface ECG. |
5,340 | Short and long QT syndromes: does QT length really matter? | The short and long QT syndromes are inherited diseases associated with an increased risk for life-threatening arrhythmias. The first case of long QT syndrome (LQTS) was reported more than 150 years ago, and the study of this disease led to crucial advancement of our understanding of channelopathies and associated ventricular arrhythmias. Ten years ago, Gussak et al. reported four cases of idiopathic ventricular fibrillation in individuals from a family with a history of sudden cardiac death exhibited very short QT interval and labeled the disease: short QT syndrome (SQTS). Over this decade, the SQTS was found to be a rare inherited syndrome with the potential to provide novel insights into the main mechanisms of cardiac arrhythmogenicity. In this review, we discuss these mechanisms and provocatively question the role of the QT interval duration as a surrogate marker of increased risk for arrhythmia in both the LQTS and the SQTS. |
5,341 | Distribution of neuropathological lesions in pig brains after different durations of cardiac arrest. | To evaluate all brain regions reported to be selectively vulnerable to global ischaemia in a pig cardiac arrest model with different durations of no-flow by establishing a semi-quantitative brain histopathologic scoring system and to compare histological damage with neurological deficits.</AbstractText>In a prospective randomised laboratory investigation, 35 female Large White pigs weighing 35-45 kg underwent ventricular fibrillation cardiac arrest for 0, 7, 10 or 13 min. In the brains of all animals that survived until the final endpoint (72 h post-arrest), 22 distinct regions were evaluated on paraffin-embedded sections in terms of type and extent of lesions. The results of the histological examination were compared to the results of a neurological outcome evaluation after 72 h.</AbstractText>Significant differences were found in all cortex regions, the caudate nucleus and putamen, the hippocampal formation, the cerebellar cortex, and the thalamus between the ischaemic groups (7- and 10-min groups) and the control group (0-min group). No 13-min group animal survived. The main findings were neuronal necrosis and oedema. In animals from the 10-min group, many neurons were reabsorbed in the cerebral cortex, caudate nucleus and cerebellar granule cell layer. There was a highly significant correlation between histological damage and neurological deficits.</AbstractText>The pattern of neuronal lesions in this pig model bear good resemblance to the pattern known in humans and other animal models. The amount of histological lesions in selectively vulnerable brain regions correlates to neurological outcome.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,342 | Epicardial left atrial appendage and biatrial appendage accessory pathways. | Acute success rates of accessory pathway ablation for Wolff-Parkinson-White (WPW) syndrome can exceed 95%, with rare failures attributed to anatomically complex epicardial connections. Right atrial appendage to right ventricle pathways have been reported, but their left-sided counterparts have only recently been described.</AbstractText>The purpose of this study was to report three unique cases of WPW syndrome in children with left atrial appendage and biatrial appendage connections.</AbstractText>Three young patients with high-risk accessory pathways (accessory pathway effective refractory period = 190-240 ms) had unsuccessful endocardial ablations despite aggressive efforts with various catheter techniques. One patient had a left atrial appendage to left ventricular connection; the other two had biatrial appendage pathways connected to their respective ventricular surfaces. The latter two patients had a history of ventricular fibrillation: one experiencing ventricular fibrillation in the electrophysiology laboratory and the other suffering from ventricular fibrillation arrest at home. All three patients were taken to the operating room, where the appendages were noted to be diffusely adherent to their ventricles by fibrofatty connections. Dissection of the appendages led to loss of preexcitation and no further tachycardia.</AbstractText>Surgical management of atrial appendage accessory pathways should be considered if aggressive attempts at endocardial ablation have failed.</AbstractText>Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,343 | Do traditional VT zones improve outcome in primary prevention ICD patients? | We reviewed outcomes in our primary prevention implantable cardioverter defibrillator (ICD) population according to whether the device was programmed with a single ventricular fibrillation (VF) zone or with two zones including a ventricular tachycardia (VT) zone in addition to a VF zone.</AbstractText>This retrospective study examined 137 patients with primary prevention ICDs implanted at our institution between 2004 and 2006. Device programming and events during follow-up were reviewed. Outcomes included all-cause mortality, time to first shock, and incidence of shocks.</AbstractText>Eighty-seven ICDs were programmed with a single VF zone (mean >193 ± 1 beats per minute [bpm]) comprising shocks only. Fifty ICDs had two zones (mean VT zone >171 ± 2 bpm; VF zone >205 ± 2 bpm), comprising antitachycardia pacing (100%), shocks (96%), and supraventricular (SVT) discriminators (98%) . Discriminator "time out" functions were disabled. Mean follow-up was 30 ± 0.5 months and similar in both groups. All-cause mortality (12.6% and 12.0%) and time to first shock were similar. However, the two-zone group received more shocks (32.0% vs 13.8% P = 0.01). Five of 16 shocks in these patients were inappropriate for SVT rhythms. The single-zone group had no inappropriate shocks for SVTs. Eighteen of 21 appropriate shocks were for ventricular arrhythmias at rates >200 bpm (three VF, 15 VT). This suggests that primary prevention ICD patients infrequently suffer ventricular arrhythmias at rates <200 bpm and that ATP may play a role in terminating rapid VTs.</AbstractText>Patients with two-zone devices received more shocks without any mortality benefit.</AbstractText>©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,344 | Incidence, risk factors, and clinical outcomes of atrial fibrillation and atrial flutter after heart transplantation. | Atrial fibrillation (AF) and atrial flutter (AFL) after heart transplantation (HT) has been associated with increased mortality. Diverse incidence rates have been reported to date, with no clear classification according to the time of onset of such arrhythmias. We determined the incidence of AF/AFL using the time of onset after HT and analyzed the associated risk factors and outcomes. We performed a retrospective study of 228 HT recipients (March 1996 to July 2007), including donor and recipient demographics, gender mismatch, ischemia time, surgical anastomosis, time of onset of AF/AFL, acute cellular rejection, left ventricular systolic function, and all-cause mortality. The mean age of the donors (81% men) was 30 +/- 12 years and of the recipients (78% men) was 53 +/- 11 years. AF/AFL occurred in 45 patients (20%): 24 (11%) in the first 30 days, 10 (4%) within the 31 days to 1 year, and 11 (5%) after 1 year. When the patients with AF/AFL were compared to those with sinus rhythm, the significant difference was the older mean age of the donors (p = 0.001) and the recipients (p = 0.02). The all-cause mortality rate was 43% for those with AF/AFL compared to 23% for those with sinus rhythm (hazard ratio 2.45; 95% confidence interval 1.2 to 4.8), mostly driven by the greater mortality in the later-onset AF/AFL group (>30 days after HT). In conclusion, AF and AFL have an incidence of 20% after HT and are associated with increased overall mortality compared to that in patients in sinus rhythm. AF/AFL is more common within the first 30 days of HT, with an overall incidence of 20%. Older donor and recipient age is a risk factor associated with AF/AFL. |
5,345 | Atrial arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia and ventricular tachycardia. | Information on atrial arrhythmia associated with right ventricular cardiomyopathy/dysplasia (ARVC/D) is limited. In 36 patients with task force criteria for ARVC/D and history of ventricular tachycardia (VT), we confirmed the incidence and type of atrial arrhythmia, onset related to referral for VT ablation, fastest documented ventricular rate, management, and clinical and hemodynamic factors associated with their development. Thirty-six patients (28 men) had a mean age of 47 years (range 17 to 80) and mean follow-up of 56 +/- 44 months. Thirty-five patients (97%) had implantable cardioverter-defibrillator (ICD) devices, 15 with atrial leads. Fifteen of 36 patients (42%) had documented atrial arrhythmias, with atrial flutter (aFL) in 11, atrial fibrillation (AF) in 11 patients, and aFL and AF in 7 patients. Maximum heart rate noted with atrial arrhythmia was 62 to 150 beats/min. In 9 patients, initial atrial arrhythmia preceded or was concurrent with presentation for VT ablation. In the remaining 6 patients, atrial arrhythmia (symptomatic in 4 patients) followed VT presentation. Three of these patients received ICD shock therapy for atrial arrhythmias. Seven of 11 patients with recurrent aFL required aFL ablation, 1 patient underwent His-bundle ablation for AF with rapid rate, and 8 patients required long-term drug therapy for AF control. Atrial arrhythmias were more common in patients with RV enlargement and moderate/severe tricuspid regurgitation. In conclusion, in patients with ARVC/D and VT, atrial arrhythmias are common, frequently necessitate ablative or pharmacologic treatment, and are more common in patients with moderate/severe tricuspid regurgitation and markedly enlarged right ventricle. |
5,346 | Effect of cardiac resynchronization therapy on subendo- and subepicardial left ventricular twist mechanics and relation to favorable outcome. | The analysis of left ventricular (LV) mechanics provides novel insights into the effects of cardiac resynchronization therapy (CRT) on LV performance. Currently, advances in speckle-tracking echocardiographic analysis have permitted the characterization of subendocardial and subepicardial LV twist. The aim of this study was to investigate the role of the acute changes in subendocardial and subepicardial LV twist for the prediction of midterm beneficial effects of CRT. A total of 84 patients with heart failure scheduled for CRT were recruited. All patients underwent echocardiography before and <48 hours after CRT implantation and at 6-month follow-up. The assessment of LV volumes, ejection fractions, and mechanical dyssynchrony (systolic dyssynchrony index) was performed with real-time 3-dimensional echocardiography. The assessment of subendocardial and subepicardial LV twist was performed with 2-dimensional speckle-tracking echocardiography. A favorable outcome was defined as the occurrence of a reduction > or =15% in LV end-systolic volume associated with an improvement of > or =1 New York Heart Association functional class at 6-month follow-up. At 6-month follow-up, 53% of the patients showed favorable outcomes. Ischemic cause of heart failure, baseline systolic dyssynchrony index, immediate improvement in the LV ejection fraction, immediate improvement in systolic dyssynchrony index, and immediate improvement in subendocardial and subepicardial LV twist were significantly related to favorable outcomes. However, in multivariate logistic regression analysis, only the immediate improvement of subepicardial LV twist was independently related to favorable outcomes (odds ratio 2.31, 95% confidence interval 1.29 to 4.15, p = 0.005). Furthermore, the immediate improvement of subepicardial LV twist had incremental value over established parameters. In conclusion, the immediate improvement of subepicardial LV twist (but not subendocardial LV twist) is independently related to favorable outcomes after CRT. |
5,347 | Comparison of detection of arrhythmias in patients with chronic heart failure secondary to non-ischemic versus ischemic cardiomyopathy by 1 versus 7-day holter monitoring. | The purpose of this study was to compare the diagnostic sensitivity of 1-day Holter monitoring versus 7-day Holter monitoring (7DH) to detect atrial and ventricular arrhythmias in a population of stable patients with chronic heart failure and left ventricular dysfunction. Sixty-three consecutive stable patients with chronic heart failure with left ventricular ejection fractions < or =50% were included. Blood samples were obtained, the Minnesota Living With Heart Failure Questionnaire was administered, and echocardiography, 6-minute walk tests, and 7DH were performed at enrollment. The mean ejection fraction was 35.8 +/- 9.8%, and the mean age was 55.5 +/- 13.9 years. Seven-day Holter monitoring did not significantly increase the detection of nonsustained atrial tachycardia or atrial fibrillation. In contrast, the incidence of nonsustained ventricular tachycardia increased in nonischemic patients from 35.1% on day 1 to 54.1% on day 7 (p = 0.01). In ischemic patients, the sensitivity increased from 11.5% to 46.2% (p = 0.004). Two patients without nonsustained ventricular tachycardia on day 1 had episodes of 13 and 16 beats on days 3 and 6 of monitoring. In patients with left ventricular ejection fractions >35% and N-terminal-pro-brain natriuretic peptide levels <1,000 pg/ml, no episodes of nonsustained ventricular tachycardia were detected on day 1 in nonischemic and ischemic patients, but 7DH detected 3 new patients in each group. In conclusion, 7DH clearly improves the detection and allows a better characterization of ventricular arrhythmic episodes but seems to be less useful for supraventricular events. |
5,348 | Effect of high doses of magnesium on converting ibutilide to a safe and more effective agent. | Ibutilide is a class III antiarrhythmic agent indicated for cardioversion of atrial fibrillation and atrial flutter to sinus rhythm (SR). The most serious complication of ibutilide is torsades de pointes (TdP). Magnesium has been successfully used for the treatment of TdP, but its use as a prophylactic agent for this arrhythmia has not yet been established. The present study investigated whether high dose of magnesium would increase the safety and efficacy of ibutilide administration. A total of 476 patients with atrial fibrillation or atrial flutter who were candidates for conversion to SR were divided into 2 groups. Group A consisted of 229 patients who received ibutilide to convert atrial fibrillation or atrial flutter to SR. Group B consisted of 247 patients who received an intravenous infusion of 5 g of magnesium sulfate for 1 hour followed by the administration of ibutilide. Then, another 5 g of magnesium were infused for 2 additional hours. Of the patients in groups A and B, 154 (67.3%) and 189 (76.5%), respectively, were converted to SR (p = 0.033). Ventricular arrhythmias (sustained, nonsustained ventricular tachycardia, and TdP) occurred significantly more often in group A than in group B (7.4% vs 1.2%, respectively, p = 0.002). TdP developed in 8 patients (3.5%) in group A and in none (0%) in group B (p = 0.009). The administration of magnesium (despite the high doses used) was well tolerated. In conclusion, the administration of high doses of magnesium probably makes ibutilide a much safer agent, and magnesium increased the conversion efficacy of ibutilide. |
5,349 | Hemiazygous coil placement for high-defibrillation thresholds in a patient with a right-sided implantable cardioverter defibrillator. | A 41-year-old man underwent implantation of a right-sided implantable cardioverter defibrillator after removal of an infected left-sided system. Defibrillation threshold (DFT) testing on the right-sided system failed to convert ventricular fibrillation at maximum device output (35 J) compared with a DFT of less than 15 J on the previous left-sided system. A single-coil lead was selectively placed into the hemiazygous vein, which courses leftward of the spine in a posterior-anterior projection, resulting in an improved shocking vector and reduction in DFTs to less than 25 J. |
5,350 | Implantation of a fully subcutaneous ICD in children. | The subcutaneous implantable cardioverter defibrillator (S-ICD) from Cameron Health (San Clemente, CA, USA) does not require a lead to be placed on or in the heart. Such a device, being subcutaneous, has potential benefits in children who require ICDs where problems largely relate to transvenous or epicardial leads and inappropriate shocks. The S-ICD was approved for use in Europe in June 2009 and recently a study commenced to acquire data in 330 patients in order to submit to the FDA. We shall describe the implantation of the S-ICD in two children aged 10 and 12 years at our institution. |
5,351 | An acute myocardial infarction case that survived an out-of-hospital cardiac arrest in which prominent ischemic J waves were documented. | We describe a case of a myocardial infarction, in which prominent ischemic J waves were documented during recurrent ventricular fibrillation attacks. The patient was referred to our hospital to treat an out-of hospital cardiac arrest. Although the 12-lead electrocardiogram obtained just after the first cardioversion did not show any apparent J waves, a J wave-like steep downsloping type ST-segment elevation associated with q waves in the inferior leads was documented during multiple episodes of ventricular fibrillation. Our report revealed the appearance of J waves as an important marker for lethal arrhythmias in acute ischemia. |
5,352 | Significant impairment of left atrial function in patients with cardioembolic stroke caused by paroxysmal atrial fibrillation. | Patients with cardioembolic stroke (CE) caused by paroxysmal atrial fibrillation (Paf) sometimes show normal sinus rhythm on admission, which makes it difficult to diagnose them as having CE. The present study examined the differences in echocardiographic findings between patients with CE caused by Paf (the Paf-CE group) and those with non-cardiogenic embolic ischemic stroke (the Non-CE group).</AbstractText>We examined thirty-two patients with embolic ischemic stroke presenting with a normal sinus rhythm upon admission to our hospital; 13 patients in the Paf-CE group and 19 patients in the Non-CE group. During admission, all patients underwent transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) at a normal sinus rhythm. The left atrial dimension, left ventricular end-diastolic dimension and left ventricular ejection fraction were measured using TTE. The left atrial appendage peak flow velocity (LAAPV), spontaneous echo-contrast in the left atrium (LASEC) and thrombus in the left atrium were evaluated using TEE.</AbstractText>Among the clinical background characteristics, hypertension was significantly more frequent in the Non-CE group than in the Paf-CE group (p<0.01). Congestive heart failure was significantly more frequent in the Paf-CE group than in the Non-CE group (p<0.05). LAAPV was significantly lower in the Paf-CE group than in the Non-CE group (34.7 cm/s vs. 64.0 cm/s, p<0.01), and the LASEC grade was significantly higher in the Paf-CE group than in the Non-CE group (p<0.01). A thrombus in the left atrium was detected in two patients in the Paf-CE group, but no thrombi were detected in any of the patients in the Non-CE group.</AbstractText>Echocardiographic evaluation is useful, as the above data indicate that the left atrial function is apparently impaired in patients with CE caused by Paf, even in a patient with an apparently normal sinus rhythm.</AbstractText> |
5,353 | Synthetic ECG generation and Bayesian filtering using a Gaussian wave-based dynamical model. | In this paper, we describe a Gaussian wave-based state space to model the temporal dynamics of electrocardiogram (ECG) signals. It is shown that this model may be effectively used for generating synthetic ECGs as well as separate characteristic waves (CWs) such as the atrial and ventricular complexes. The model uses separate state variables for each CW, i.e. P, QRS and T, and hence is capable of generating individual synthetic CWs as well as realistic ECG signals. The model is therefore useful for generating arrhythmias. Simulations of sinus bradycardia, sinus tachycardia, ventricular flutter, atrial fibrillation and ventricular tachycardia are presented. In addition, discrete versions of the equations are presented for a model-based Bayesian framework for denoising. This framework, together with an extended Kalman filter and extended Kalman smoother, was used for denoising the ECG for both normal rhythms and arrhythmias. For evaluating the denoising performance, the signal-to-noise ratio (SNR) improvement of the filter outputs and clinical parameter stability were studied. The results demonstrate superiority over a wide range of input SNRs, achieving a maximum 12.7 dB improvement. Results indicate that preventing clinically relevant distortion of the ECG is sensitive to the number of model parameters. Models are presented which do not exhibit such distortions. The approach presented in this paper may therefore serve as an effective framework for synthetic ECG generation and model-based filtering of noisy ECG recordings. |
5,354 | Absence of calcium channel alpha1C-subunit mutation in human atrial fibrillation. | L-type voltage-gated calcium channel mutation or phenotypical variation resulting from alternative splicing has been associated with sudden arrhythmogenic death and heart failure. Changes in calcium current density, protein and mRNA expression have been associated with atrial fibrillation. We studied human atrium harvested from 16 cardiac surgery patients (coronary bypass and/or valve procedures) for mutation of Ca(v)1.2 alpha(1C) (the main pore-forming subunit of L-type voltage-gated calcium channel) for an association with atrial fibrillation. Seven patients had persistent atrial fibrillation and one was resuscitated from ventricular arrhythmia. Clinical data were collected and prospectively updated for the development of arrhythmia. Four (25%) patients had new-onset postoperative paroxysmal atrial fibrillation. DNA from all atrial specimens was amplified, extracted, and sequenced. The alpha(1C)-subunit mutation was absent in all specimens obtained from all patients, regardless of heart rhythm. This suggests that atrial fibrillation is not associated with loss-of-function mutation of the main pore-forming subunit of the L-type voltage-gated calcium channel. |
5,355 | Gender-specific differences in the clinical features of hypertrophic cardiomyopathy in a community-based Japanese population: results from Kochi RYOMA study. | Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder with a broad spectrum of clinical features. Although gender may be one of the important modifying factors in HCM, there has been little information on gender differences.</AbstractText>We investigated gender-specific differences in the clinical features of HCM in a community-based Japanese population. We established cardiomyopathy registration in Kochi Prefecture named Kochi RYOMA study consisting of 9 hospitals as an unselected regional Japanese population.</AbstractText>261 patients with diagnosis of HCM were registered. At registration, 88 patients (34%) were women. Female patients were more frequently diagnosed as having HCM at ≥65 years (41% versus 27%) and had a higher ratio of familial HCM (35% versus 19%). More female patients had diagnosis of HCM due to cardiac symptoms (64% versus 40%) and were symptomatic both at diagnosis and at registration. Although the prevalence of atrial fibrillation was not different between males and females, embolic events occurred less frequently in female patients at registration than in male patients (2% versus 10%). In female patients, there were more obstructive HCM patients and fewer patients with apical HCM. Left ventricular and left atrial diameters were smaller and fractional shortening was higher in females than in males.</AbstractText>The manifestations of HCM in unselected Japanese patients differed in men and women, which suggest that hormonal, social, and genetic factors may influence the clinical presentation of HCM.</AbstractText>Copyright © 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
5,356 | Improving contemporary algorithms for implantable cardioverter-defibrillator function. | Implantable cardioverter-defibrillators (ICDs) have been shown in various clinical trials to prevent mortality from sudden cardiac death due to unstable rhythms or ventricular fibrillation. Modern ICDs use sophisticated algorithms to not only deliver therapy on the detection of a malignant rhythm but also reduce the incidence of inappropriate shocks through rhythm discrimination. Current algorithms for detection of malignant rhythms use sophisticated techniques such as real-time processing and analysis of electrograms from a transvenous lead system. The Rhythm ID feature in Boston Scientific ICDs is an example of one such algorithm used for rhythm discrimination. Rhythm ID uses the vector timing and correlation algorithm, which incorporates both timing as well as morphology information for supraventricular tachycardia discrimination. Clinical trials demonstrated high sensitivity and specificity of this feature in discriminating between ventricular tachycardia and supraventricular tachycardia (results published previously). On detection of the unknown rhythm (when the ventricular tachycardia rate detection criteria is met), the vector timing and correlation algorithm compares the unknown rhythm beat-by-beat to a stored template of normal sinus rhythm. The feature correlation coefficient computed over more than 8 points in the time-aligned signals is used for the comparison. The specific discrimination procedure of Rhythm ID depends on the mode (VR or DR) and on whether the test rhythm is an initial detected rhythm or a postshock rhythm. The normal sinus rhythm template against which the suspected rhythm is compared can be periodically updated. This article will cover some of the key aspects of the Rhythm ID feature's decision-making process and the algorithm for template update. The results of previously published clinical studies involving the algorithm's performance also will be reviewed. |
5,357 | Selective inhibition of persistent sodium current by F 15845 prevents ischaemia-induced arrhythmias. | Myocardial ischaemia is associated with perturbations of electrophysiological profile of cardiac myocytes. The persistent sodium current (I(Nap)) is one of the major contributors to ischaemic arrhythmias and appears as an attractive therapeutic target. We investigated the effects of F 15845, a new anti-anginal drug on I(Nap) and in integrative models of I(Nap)-induced arrhythmias.</AbstractText>Sodium current was investigated using patch clamp technique on wild-type and DeltaKPQ-mutated hNav1.5 channels transfected in HEK293 cells. Effects of F 15845 on action potentials (APs) were studied by the glass microelectrode technique and its anti-arrhythmic activities were investigated in ischaemia- and aconitine-induced arrhythmias in the rat.</AbstractText>We demonstrated that F 15845 is a potent blocker of I(Nap) acting from the extracellular side of the channel. Blockade of I(Nap) was voltage dependent and characterized by an almost pure tonic block. F 15845 shortened AP from rabbit Purkinje fibres, confirming its lack of pro-arrhythmic activity, and prevented AP lengthening induced by the I(Nap) activator veratridine. F 15845 did not affect APs from rabbit atria and guinea pig papillary muscle where I(Nap) is not functional, confirming its inability to affect other cardiac ionic currents. F 15845 was effective at preventing fatal ventricular fibrillation and ventricular tachycardia during coronary ligation without modifying heart rate and blood pressure, and dose dependently increased the dose threshold of aconitine required to induce ventricular arrhythmias.</AbstractText>F 15845, a novel anti-anginal drug targeting I(Nap), demonstrates new anti-arrhythmic properties which may be of therapeutic benefit against ischaemia-induced arrhythmias.</AbstractText> |
5,358 | Reduction of reperfusion-induced ventricular fibrillation and infarct size via heme oxygenase-1 overexpression in isolated mouse hearts. | Heme oxygenase-1 (HO-1), also known as heat shock protein 32 (hsp-32) is a stress induced cytoprotective protein. The present investigation evaluated the capacity of HO-1 to reduce the incidence of reperfusion-induced ventricular fibrillation (VF) and infarct size. HO-1 transgenic (Tg) mice were generated using a rat HO-1 genomic transgene. Isolated mouse hearts obtained from Tg and nontransgenic (NTg) groups were exposed to 20 min of global ischemia and 120 min of reperfusion. Epicardial ECG was recorded to monitor the incidence of reperfusion-induced VF and at the end of the reperfusion period, detection of HO-1 by immunohistochemistry and measurement of infarct size using the TTC method were carried out. Results shown here provide additional support for cardioprotective effects of HO-1 as evidenced by the reduced infarct size. Moreover, overexpression of the HO-1 efficiently reduced the incidence of ischemia/reperfusion (I/R)-induced VF in HO-1 Tg mice. |
5,359 | [News in hemodynamic monitoring, resuscitation and intensive care of patients after cardiac surgery: "Guidelines for resuscitation in cardiac arrest after cardiac surgery" of the European Association for Cardio-Thoracic Surgery]. | In order to simplify and to standardize procedures during cardiac arrest in patients after cardiac surgery and for professional medical staff education, working group of the European Association for Cardio-Thoracic Surgery issued in 2009 "Guideline for resuscitation in cardiac arest after cardiac surgery". There are several differences between these guidelines and guidelines for general population: in ventricular fibrillation, three sequential attempts at defibrillation should precede external cardiac massage; in asystole or extreme bradycardia, pacing should precede external cardiac massage. Where the above measures fail, and in pulseless electrical activity, early resternotomy is advocated. Adrenaline should not be routinely given. Also protocols for excluding reversible airway and breathing complications and for safe emergency resternotomy are given. These guidelines in very simple and professional way define rules for resuscitation of patients after cardiac surgery. It is a useful manual which will certainly find its place in daily work of professional medical staff involved in healthcare of these patients. |
5,360 | Arrhythmia burden in adults with surgically repaired tetralogy of Fallot: a multi-institutional study. | The arrhythmia burden in tetralogy of Fallot, types of arrhythmias encountered, and risk profile may change as the population ages.</AbstractText>The Alliance for Adult Research in Congenital Cardiology (AARCC) conducted a multicenter cross-sectional study to quantify the arrhythmia burden in tetralogy of Fallot, to characterize age-related trends, and to identify associated factors. A total of 556 patients, 54.0% female, 36.8+/-12.0 years of age were recruited from 11 centers. Overall, 43.3% had a sustained arrhythmia or arrhythmia intervention. Prevalence of atrial tachyarrhythmias was 20.1%. Factors associated with intraatrial reentrant tachycardia in multivariable analyses were right atrial enlargement (odds ratio [OR], 6.2; 95% confidence interval [CI], 2.8 to 13.6), hypertension (OR, 2.3; 95% CI, 1.1 to 4.6), and number of cardiac surgeries (OR, 1.4; 95% CI, 1.2 to 1.6). Older age (OR, 1.09 per year; 95% CI, 1.05 to 1.12), lower left ventricular ejection fraction (OR, 0.93 per unit; 95% CI, 0.89 to 0.96), left atrial dilation (OR, 3.2; 95% CI, 1.5 to 6.8), and number of cardiac surgeries (OR, 1.5; 95% CI, 1.2 to 1.9) were jointly associated with atrial fibrillation. Ventricular arrhythmias were prevalent in 14.6% and jointly associated with number of cardiac surgeries (OR, 1.3; 95% CI, 1.1 to 1.6), QRS duration (OR, 1.02 per 1 ms; 95% CI, 1.01 to 1.03), and left ventricular diastolic dysfunction (OR, 3.3; 95% CI, 1.5 to 7.1). Prevalence of atrial fibrillation and ventricular arrhythmias markedly increased after 45 years of age.</AbstractText>The arrhythmia burden in adults with tetralogy of Fallot is considerable, with various subtypes characterized by different profiles. Atrial fibrillation and ventricular arrhythmias appear to be influenced more by left- than right-sided heart disease.</AbstractText> |
5,361 | Impact of myocardial perfusion abnormality on prognosis in patients with non-ischemic dilated cardiomyopathy. | Myocardial perfusion imaging shows various patterns in patients with non-ischemic dilated cardiomyopathy (DCM). However, influences of regional abnormalities of myocardial perfusion or ventricular wall motion on prognosis in DCM patients remains to be clarified. Accordingly, we investigated a relation between myocardial perfusion patterns and long-term prognosis in DCM patients.</AbstractText>Sixty-two patients were divided into 2 groups according to patterns of (99m)Tc-Tetrofosmin scintigraphy, i.e. large focal defects (focal) and minimally impaired perfusion or multiple small defects (non-focal). There were no differences between the 2 groups in left ventricular (LV) end-diastolic dimensions (63.4 ± 9.1 and 63.8.4 ± 7.5mm, respectively) and LV ejection fraction (30.3 ± 9.2 and 27.9 ± 7.8%, respectively), indicating LV systolic dysfunction was comparable between the groups. The focal group had a higher prevalence of brain natriuretic peptide ≧ 200 ng/dl and plasma norepinephrine ≧ 500 pg/ml than the non-focal group (p<0.05), and had longer QRS durations (p<0.05). The focal group had non-sustained ventricular tachycardia (VT) (p<0.05) on 24-h electrocardiogram recording and a history of VT/ventricular fibrillation more frequently (p<0.05), and had higher New York Heart Association functional class than the non-focal group (p<0.05). The mortality was significantly higher in the focal group (56.0%) than in the non-focal group (28.6%) and the survival curves revealed worse prognosis in the focal group during a follow-up period of 5.3 ± 2.8 years.</AbstractText>Non-ischemic DCM patients with focal defects are accompanied by more advanced heart failure and poor prognosis compared to those with minimally impaired perfusion or multiple small defects, despite comparable LV systolic dysfunction.</AbstractText>Copyright © 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
5,362 | Circadian, weekly, and seasonal mortality variations in out-of-hospital cardiac arrest in Japan: analysis from AMI-Kyoto Multicenter Risk Study database. | Several studies have reported circadian, weekly, and seasonal variations in the rates of out-of-hospital cardiac arrest (OHCA). However, variations in the mortality of OHCA are not well known.</AbstractText>We investigated the 1396 consecutive cases of OHCA with cardiac etiology between October 2004 and September 2008. There were 2 peaks in the occurrence of OHCA in early morning and late evening. There was a weekly pattern with an increased incidence on Mondays. We found a significant seasonal variation in the frequency of events, with a maximum during winter. There was a trend of reduced mortality in warmest 3 months, especially among a subgroup of ventricular fibrillation/pulseless ventricular tachycardia with arrest witnessed.</AbstractText>The present analyses demonstrated circadian, weekly and seasonal variations in the occurrence, and a seasonal variation in mortality in OHCA. Changes in temperature might influence the severity of OHCA and change the rate of success of cardiopulmonary resuscitation.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,363 | Analysis of transthoracic impedance during real cardiac arrest defibrillation attempts in older children and adolescents: are stacked-shocks appropriate? | In 2005, the AHA changed the treatment recommendation for shockable rhythms from 3 transthoracic stacked-shocks to a single shock followed by immediate chest compressions. The stacked-shock recommendation was based on low first-shock efficacy of monophasic waveforms and the theoretical decrease in transthoracic impedance (TTI) following each shock. The objective of this study was to characterize TTI following biphasic defibrillation attempts in children ≥ 8 yrs during cardiac arrest to assess whether a stacked-shock approach may be appropriate to improve defibrillation success.</AbstractText>TTI (Ohms (Ω)) was collected via standard anterior-apical defibrillator electrode pads during consecutive in-hospital cardiac arrest biphasic defibrillation attempts in children ≥ 8 yrs. Analytic data points for TTI were: 0.1s pre-shock (baseline); post-shock at 0.1, 0.5, 1.0, 1.5, and 2.0 s. TTI variables analyzed with descriptive summaries/paired t-test. p values < 0.05 considered statistically significant after correction for multiple comparisons.</AbstractText>Analysis yielded 13 evaluable shock events during 5 cardiac arrests (mean age 14.3 ± 5 yrs, weight 47.4 ± 7.3 kg) between September 2006 and May 2009. Compared to 0.1s pre-shock baseline values (56.8 ± 23.4 Ω), TTI was significantly lower immediately 0.1s post-shock (55.2 ± 22.2 Ω, p = 0.003). Post-shock mean difference from baseline was 1.6 Ω at 0.1s (p = 0.015), 1.4 Ω at 0.5s (p = 0.019) 1.4 Ω at 1.0 s (p = 0.023), 1.1 Ω at 1.5 s (p = 0.028), and 0.95 Ω at 2.0 s (p = 0.096). Time to recharge our clinical defibrillators to standard biphasic shock dose was 2.80 ± 0.05 s.</AbstractText>During cardiac arrests in children ≥ 8 yrs, TTI decreased after biphasic shocks, but the limited magnitude and duration of TTI changes suggest that stacked-shocks would not improve defibrillation success.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,364 | Clinical predictors of survival in patients treated with therapeutic hypothermia following cardiac arrest. | Therapeutic hypothermia has been shown to provide neuroprotection and improved survival in patients suffering a cardiac arrest. We report outcomes of consecutive patients receiving therapeutic hypothermia for cardiac arrest and describe predictors of short and long-term survival.</AbstractText>Eighty patients receiving therapeutic hypothermia between January 2005 and December 2008 were identified and categorized as those who survived and died. Outcomes and predictors of survival were determined.</AbstractText>Forty-five patients (56%) survived to hospital discharge and were alive at 30 days and among survivors 41 (91%) were alive 1 year after discharge. Survivors were younger, were more likely to present with VF, required less epinephrine during resuscitation, were more likely to have preserved renal function, and were less likely to be taking beta-blockers and ACE inhibitors. Predictors of survival included VF on presentation (OR 14.9, CI 2.7-83.2, p=0.002), pre-cardiac arrest aspirin use (OR 9.7, CI 1.6-61.1, p=0.02), return of spontaneous circulation <20 min (OR 9.4, CI 2.2-41.1, p=0.003), absence of coronary artery disease (OR 5.3, CI 1.1-24.7, p=0.002) and preserved renal function.</AbstractText>Therapeutic hypothermia is useful in the treatment of patients suffering a cardiac arrest. Several clinical factors may aid in predicting patients who are likely to survive after a cardiac arrest.</AbstractText>Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,365 | Pre- and post-operative cardiac evaluation of dogs undergoing lobectomy and pneumonectomy. | This study aimed to assess the influence of lobectomy and pneumonectomy on cardiac rhythm and on the dimensions and function of the right-side of the heart. Twelve dogs undergoing lobectomy and eight dogs undergoing pneumonectomy were evaluated preoperatively and one month postoperatively with electrocardiography and Doppler echocardiography at rest. Pulmonary artery systolic pressure (PASP) was estimated by the tricuspid regurgitation jet (TRJ) via the pulse wave Doppler velocity method. Systemic inflammatory response syndrome criteria (SIRS) were also evaluated based on the clinical and hematological findings in response to lobectomy and pneumonectomy. Following lobectomy and pneumonectomy, we predominantly detected atrial fibrillation and varying degrees of atrioventricular block (AVB). Dogs that died within seven days of the lobectomy (n = 2) or pneumonectomy (n = 1) had complete AVB. Preoperative right atrial, right ventricular, and pulmonary artery dimensions increased gradually during the 30 days (p < 0.05) following pneumonectomy, but did not undergo significant changes during that same period after lobectomy. Mean PASP was 56.0 +/- 4.5 mmHg in dogs having significant TRJ after pneumonectomy. Pneumonectomy, but not lobectomy, could lead to increases (p < 0.01) in the SIRS score within the first day post-surgery. In brief, it is important to conduct pre- and postoperative cardiac evaluation of dogs undergoing lung resections because cardiac problems are a common postoperative complication after such surgeries. In particular, complete AVB should be considered a lifethreatening complication after pneumonectomy and lobectomy. In addition, pneumonectomy appears to increase the likelihood of pulmonary hypertension development in dogs. |
5,366 | The Intermountain Risk Score (including the red cell distribution width) predicts heart failure and other morbidity endpoints. | The complete blood count (CBC) and basic metabolic profile are common, low-cost blood tests, which have previously been used to create and validate the Intermountain Risk Score (IMRS) for mortality prediction. Mortality is the most definitive clinical endpoint, but medical care is more easily applied to modify morbidity and thereby prevent death. This study tested whether IMRS is associated with clinical morbidity endpoints.</AbstractText>Patients seen for coronary angiography (n = 3927) were evaluated using a design similar to a genome-wide association study. The Bonferroni correction for 102 tests required a P-value of ≤ 4.9 × 10⁻⁴ for significance. A second set of angiography patients (n = 10 413) was used to validate significant findings from the first patient sample. In the first patient sample, IMRS predicted heart failure (HF) (P(trend) = 1.6 × 10(-26)), coronary disease (P(trend) = 2.6 × 10(-11)), myocardial infarction (MI) (P(trend) = 3.1 × 10(-25)), atrial fibrillation (P(trend) = 2.5 × 10(-20)), and chronic obstructive pulmonary disease (P(trend) = 4.7 × 10⁻⁴). Even more, IMRS predicted HF readmission [hazard ratio (HR) = 2.29/category, P(trend) = 1.2 × 10⁻⁶), incident HF (HR = 1.88/category, P(trend) = 0.02), and incident MI (HR = 1.56/category, P(trend) = 4.7 × 10⁻⁴). These findings were verified in the second patient sample.</AbstractText>Intermountain Risk Score, a predictor of mortality, was associated with morbidity endpoints that often lead to mortality. Further research is required to fully characterize its clinical utility, but its low-cost CBC and basic metabolic profile composition may make it ideal for initial risk estimation and prevention of morbidity and mortality. An IMRS web calculator is freely available at http://intermountainhealthcare.org/IMRS.</AbstractText> |
5,367 | Sudden cardiac death secondary to demonstrated reperfusion ventricular fibrillation in a woman with Takotsubo cardiomyopathy. | Takotsubo cardiomyopathy is a left ventricle cardiomyopathy characterized by a reversible dyskinesia responsible for the typical apical ballooning aspect. The disease is considered benignant with a full recovery within a few weeks. We present the case of a 52-year-old woman who presented with angina diagnosed with Takotsubo cardiomyopathy on the basis of both noninvasive (electrocardiography, echocardiography) and invasive (angiography) exams. At discharge, a Holter monitor was fitted to the patient. During the recording the patient faced sudden cardiac death. The analysis of the Holter traces allowed some speculations on the mechanism of this unexpected arrhythmic death. The cause of the fatal ventricular fibrillation appears to be the fast reperfusion following a short occlusion of an epicardial coronary artery. This case highlights the epicardial vasospasm as an important pathogenic mechanism of the syndrome and the possible usefulness of diagnostic tests able to elicit the spasm susceptibility and guide a more targeted pharmacological therapy. Some considerations are also possible on the cellular processes linking the rapid reperfusion and the arrhythmias onset. |
5,368 | [Modern technology in cardiovascular medicine]. | Despite basic physiologic principles being well known for more than 300 years, the diagnosis and therapy of cardiovascular diseases are still in their early beginnings. For example, 100 years ago sudden cardiac arrest was regarded as the result of toxic gases. The diagnosis of ventricular fibrillation or treatment with a defibrillator are very recent developments. We are currently experiencing a technological revolution, which is rapidly changing cardiovascular medicine. This publication is focused on electrical devices and tries to identify some of the innovation mainstreams using a few examples to demonstrate these. Four megatrends are explained in more detail: the influence of wireless technology, information technology, micro systems technology, and thinking in systems. This paper is aimed at stimulating active researchers and engineers to detect the rapid changes that we often do not observe in our daily work. The author hopes that this stimulation will lead to new ideas and combinations. |
5,369 | Body mass index and survival after in-hospital cardiac arrest. | The quality and effectiveness of resuscitation processes may be influenced by the patient's body mass index (BMI); however, the relationship between BMI and survival after in-hospital cardiac arrest has not been previously studied.</AbstractText>We evaluated 21 237 adult patients with an in-hospital cardiac arrest within the National Registry for Cardiopulmonary Resuscitation (NRCPR). We examined the association between BMI (classified as underweight [<18.5 kg/m(2)], normal [18.5 to 24.9 kg/m(2)], overweight [25.0 to 29.9 kg/m(2)], obese [30.0 to 34.9 kg/m(2)], and very obese [≥35.0 kg/m(2)]) and survival to hospital discharge using multivariable logistic regression, after stratifying arrests by rhythm type and adjusting for patient characteristics. Of 4499 patients with ventricular fibrillation or pulseless ventricular tachycardia as initial rhythm, 1825 (40.6%) survived to discharge. After multivariable adjustment, compared with overweight patients, underweight (odds ratio [OR], 0.59; 95% confidence interval [CI], 0.41 to 0.84; P=0.003), normal weight (OR, 0.75; 95% CI, 0.63 to 0.89; P<0.001), and very obese (OR, 0.78; 95% CI, 0.63 to 0.96; P=0.02) had lower rates of survival, whereas obese patients had similar rates of survival (OR, 0.87; 95% CI, 0.72 to 1.06; P=0.17). In contrast, of 16 738 patients with arrests caused by asystole or pulseless electric activity, only 2501 (14.9%) survived. After multivariable adjustment, all BMI groups had similar rates of survival except underweight patients (OR, 0.67; 95% CI, 0.54 to 0.82; P<0.001).</AbstractText>For cardiac arrest caused by shockable rhythms, underweight, normal weight, and very obese patients had lower rates of survival to discharge. In contrast, for cardiac arrest caused by nonshockable rhythms, survival to discharge was similar across BMI groups except for underweight patients. Future studies are needed to clarify the extent to which BMI affects the quality and effectiveness of resuscitation measures.</AbstractText> |
5,370 | Are new resuscitation guidelines better? Experience of an Asian metropolitan hospital. | Cardiopulmonary resuscitation (CPR) guidelines were revised in 2005 based on new evidence and expert consensus. However, the benefits of the new guidelines remain undetermined and their influence has not been published in Asia. This study aimed to evaluate the impact of implementing the new resuscitation guidelines and identify factors that influence the discharge survival of out-of-hospital cardiac arrest (OHCA) patients in an Asian metropolitan city.</AbstractText>This was an observational cohort study of all OHCA patients seen by the emergency medical service during the period before (Nov 2003 to Oct 2005) and after (May 2006 to Oct 2008) implementing the new resuscitation guidelines. Detailed clinical information was recorded using the Ustein style template. Statistical analysis was done using X2 test or t-test for univariate analysis and the logistic regression model for multivariate analysis.</AbstractText>There were 463 patients before and 430 patients after the new guidelines who received resuscitation. The rate of recovery of spontaneous circulation (ROSC), survival-to-intensive care unit (ICU) admission, and survival-to-hospital discharge all showed no benefits regarding the new resuscitation guidelines (ROSC: 42% vs 39%, P = 0.32; Survival-to-ICU admission: 33% vs 30%, P = 0.27; survival-to-hospital discharge: 10% vs 7%, P = 0.09). The rate of ventricular fibrillation/pulseless ventricular tachycardia (VF/pulseless VT), rate of witnessed arrest, and rate of bystander CPR were much lower than in Western studies. After multivariate logistic regression, factors related to discharge survival were witnessed arrest and initial rhythm with VF/pulseless VT. The new resuscitation guidelines did not significantly influence the discharge survival.</AbstractText>We did not observe any improvement in survival after implementing the new guidelines. Independent factors of survival-to-hospital discharge are witnessed arrest and initial rhythm with VF/pulseless VT. Because the rates of VF/pulseless VT and bystander CPR in Asia are low, popularising CPR training programmes and increasing the rate of bystander CPR may be more important for improving OHCA survival rates than frequent guideline changes.</AbstractText> |
5,371 | An eight year review of exercise-related cardiac arrests. | Exercise-related cardiac arrest is uncommon, however it is devastating when it occurs in otherwise healthy adults. This study aims to identify the characteristics of exercise-related cardiac arrest in the study population and estimate the overall survival rate.</AbstractText>This is a retrospective observational study of exercise-related cardiac arrest in Singapore. Patients with exercise-related out of hospital cardiac arrest (OHCA) were selected from the Cardiac Arrest and Resuscitation Epidemiology (CARE) database, which is a prospective cardiac arrest registry, derived from ambulance records, emergency department and hospital discharge records. Patient characteristics, cardiac arrest circumstances and outcomes were studied.</AbstractText>Fifty-fi ve cases of exercise-related cardiac arrests were identified from December 2001 to January 2008. Mean age was 50.9 years with a male predominance of 96.4%. Eighty percent of the exercise-related cardiac arrests were witnessed, however only 58.2% of the patients received bystander cardiopulmonary resuscitation (CPR). The fi rst presenting rhythm was ventricular fibrillation (VF) in 40% of the patients, followed by asystole (38.2%). Of 96.2% of the patients who died from cardiac causes, coronary artery disease was the main etiology for 54%. The 30-day survival rate was 5.5%.</AbstractText>We found that exercise-related cardiac arrest causes significant mortality in our community. Increased CPR training among the public, easy access to defibrillators and faster emergency medical service (EMS) response time could improve the outcome of exercise-related cardiac arrests. A comprehensive pre-participation screening for competitive exercises should be outlined for primary prevention of exercise-related cardiac arrest. A better reporting system for exercise-related cardiac arrest is needed.</AbstractText> |
5,372 | Aldehyde dehydrogenase activation prevents reperfusion arrhythmias by inhibiting local renin release from cardiac mast cells. | Renin released by ischemia/reperfusion from cardiac mast cells activates a local renin-angiotensin system (RAS). This exacerbates norepinephrine release and reperfusion arrhythmias (ventricular tachycardia and fibrillation), making RAS a new therapeutic target in myocardial ischemia.</AbstractText>We investigated whether ischemic preconditioning (IPC) prevents cardiac RAS activation in guinea pig hearts ex vivo. When ischemia/reperfusion (20 minutes of ischemia/30 minutes of reperfusion) was preceded by IPC (two 5-minute ischemia/reperfusion cycles), renin and norepinephrine release and ventricular tachycardia and fibrillation duration were markedly decreased, a cardioprotective anti-RAS effect. Activation and blockade of adenosine A(2b)/A(3) receptors and activation and inhibition of protein kinase Cepsilon (PKCepsilon) mimicked and prevented, respectively, the anti-RAS effects of IPC. Moreover, activation of A(2b)/A(3) receptors or activation of PKCepsilon prevented degranulation and renin release elicited by peroxide in cultured mast cells (HMC-1). Activation and inhibition of mitochondrial aldehyde dehydrogenase type-2 (ALDH2) also mimicked and prevented, respectively, the cardioprotective anti-RAS effects of IPC. Furthermore, ALDH2 activation inhibited degranulation and renin release by reactive aldehydes in HMC-1. Notably, PKCepsilon and ALDH2 were both activated by A(2b)/A(3) receptor stimulation in HMC-1, and PKCepsilon inhibition prevented ALDH2 activation.</AbstractText>The results uncover a signaling cascade initiated by A(2b)/A(3) receptors, which triggers PKCepsilon-mediated ALDH2 activation in cardiac mast cells, contributing to IPC-induced cardioprotection by preventing mast cell renin release and the dysfunctional consequences of local RAS activation. Thus, unlike classic IPC in which cardiac myocytes are the main target, cardiac mast cells are the critical site at which the cardioprotective anti-RAS effects of IPC develop.</AbstractText> |
5,373 | Gene therapy strategies for cardiac electrical dysfunction. | Cardiac disease is frequently associated with abnormalities in electrical function that can severely impair cardiac performance with potentially fatal consequences. The available therapeutic options have some efficacy but are far from perfect. The curative potential of gene therapy makes it an attractive approach for the treatment of cardiac arrhythmias. To date, gene therapy research strategies have targeted three major classes of cardiac arrhythmias: (1) ventricular arrhythmias, (2) atrial fibrillation, and (3) bradyarrhythmias. Various vehicles for gene transfer have been employed with adeno-associated viral gene delivery being the preferred choice for long-term gene expression and adenoviral gene delivery for short-term proof-of-concept work. In combination with the development of novel delivery methods, gene therapy may prove to be an effective strategy to eliminate the most debilitating of arrhythmias. This article is part of a Special Section entitled "Special Section: Cardiovascular Gene Therapy". |
5,374 | The effects of epinephrine on outcomes of normothermic and therapeutic hypothermic cardiopulmonary resuscitation. | To investigate the effects of epinephrine when administered during either normothermic or therapeutic hypothermic cardiopulmonary resuscitation on postresuscitation myocardial and cerebral function and survival.</AbstractText>Prospective, randomized, placebo-controlled experimental study.</AbstractText>University-affiliated animal research laboratory.</AbstractText>Thirty-two healthy male Sprague-Dawley rats.</AbstractText>Ventricular fibrillation was induced and untreated for 8 mins. The animals were then randomly assigned to one of four groups: normothermic placebo control; normothermic epinephrine; hypothermic placebo control; and hypothermic epinephrine. Hypothermia was initiated coincident with the start of cardiopulmonary resuscitation. The blood temperature was reduced and maintained at 32 ± 0.2°C and continued for 4 hrs after resuscitation. Normothermic animals were maintained at 37 ± 0.2°C. Either placebo or epinephrine (20 μg/kg) was administered 5 mins after the start of cardiopulmonary resuscitation and 3 mins before defibrillation.</AbstractText>Postresuscitation cardiac output, ejection fraction, and myocardial performance index were measured hourly for 4 hrs after resuscitation; neurologic deficit scores were measured daily for 7 days, and durations of survival were observed for up to 3 mos. Except for three normothermic control animals, all animals were resuscitated. When epinephrine was administered during normothermic cardiopulmonary resuscitation, postresuscitation myocardial function was severely impaired when compared with the normothermic control group. However, postresuscitation myocardial function was significantly better in animals treated with epinephrine during hypothermic cardiopulmonary resuscitation when compared with hypothermic controls. This was associated with significantly fewer postresuscitation ventricular arrhythmias, less ST-segment elevation, better postresuscitation neurologic deficit scores, and longer duration of survival.</AbstractText>Epinephrine, when administered during normothermic cardiopulmonary resuscitation, significantly increases the severity of postresuscitation myocardial dysfunction and decreases the duration of survival. These detrimental effects of epinephrine, however, no longer exist when it is administered during therapeutic hypothermic cardiopulmonary resuscitation.</AbstractText> |
5,375 | Morbidity and mortality in heart failure patients treated with cardiac resynchronization therapy: influence of pre-implantation characteristics on long-term outcome. | Cardiac resynchronization therapy (CRT) improves cardiac function, heart failure symptoms, and prognosis in selected patients. Many baseline characteristics associated with heart failure may influence prognosis after CRT. The objective of this study was to evaluate the effect of several baseline characteristics in relation to long-term prognosis in heart failure patients treated with CRT.</AbstractText>A total of 716 consecutive heart failure patients treated with CRT were included in an observational registry. All available data, including clinical and echocardiographic measurements, were analysed in relation to two endpoints: all-cause mortality and a combined endpoint of all-cause mortality or major cardiovascular event. Outcome data were collected by chart review, device interrogation, and telephone contact. Mean follow-up was 25 ± 19 months. During follow-up, 141 patients (20%) died (primary endpoint). Most of these patients (61%) died due to worsening heart failure. A total of 214 patients (30%) reached the secondary endpoint. Larger left ventricular end-systolic volume, less distance covered in the 6 min walking test, poor renal function, more severe heart failure, male gender, presence of atrial fibrillation, no posterolateral left ventricular (LV) lead, and no LV dyssynchrony were associated with poor prognosis after CRT.</AbstractText>In this large single-centre registry, several baseline clinical and echocardiographic characteristics were associated with prognosis after CRT. Worsening heart failure was the main cause of death in heart failure patients treated with CRT.</AbstractText> |
5,376 | Plasma renin activity and pro-B-type natriuretic peptide levels in different atrial fibrillation types. | Renin-angiotensin system may be activated during atrial fibrillation (AF). Our aim was to evaluate plasma renin activity (PRA) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in patients with different AF types who had normal left ventricular (LV) systolic function.</AbstractText>This cross-sectional study included 97 patients with recent (<or=7 days), persistent (7 days to 12 months) and permanent AF (<or=12 months), and age- and sex-matched 30 controls with sinus rhythm. Plasma levels of PRA and NT-pro-BNP were measured and presented as median (25th-75th percentiles). Echocardiographic examination was performed in all population. Variance and logistic regression analyses were also used for multiple comparisons and independent predictors, respectively.</AbstractText>Median NT-proBNP levels were higher in overall patients with AF than in controls [114 (63-165) vs 50 (38-58) pg/ml, p=0.001), but PRA level was comparable in both groups. Similarly, NT-proBNP levels were also higher in all subtypes of AF compared with controls (p=0.05). In addition, there was a significant difference in NT-proBNP level among recent, persistent and permanent AF subtypes (p=0.001). This difference mainly derived from the recent AF subtypes. Whereas PRA level was similar in all AF subtypes and controls. Age was an independent predictor of PRA level >or=1.9 ng/ml/hour (OR=1.1, 95% CI 1.01-1.23, p=0.03). With NT-proBNP level >or=52 pg/ml, independent predictors were age (OR=1.1, 95% CI 1.01-1.19, p=0.02), presence of persistent and/or permanent AF (OR=6.8, 95% CI 1.03-45.7, p=0.04) and left atrial dimension (OR=1.2, 95% CI 1.03-1.36, p=0.02).</AbstractText>Plasma NT-proBNP levels can be associated with AF and its subtypes in patients with normal LV systolic function, whereas there was no association between PRA levels and AF.</AbstractText> |
5,377 | Efficacy of levosimendan in patients with chronic heart failure: Does rhythm matter? | Levosimendan is a relatively new inotropic agent. Unlike other inotropic agents, Levosimendan does not increase cellular calcium intake, so that, does not cause intracellular calcium overload and related arrhythmias. Atrial fibrillation (AF) was shown to be an independent risk factor for mortality and morbidity in large heart failure (HF) trials. Heart failure induces AF, AF aggravates HF and therefore they generally coexist. We conducted a study to investigate if there is any differential effect of Levosimendan in HF patients with chronic AF and without AF.</AbstractText>This is a prospective study. Consecutive patients, who were hospitalized because of acutely decompensated HF due to systolic dysfunction and decided Levosimendan administration, were enrolled. Patients were classified into two as those with AF (group A) and those with sinus rhythm (control group, group S). All patients had echocardiography before and after administration. Echocardiographic data were evaluated by ANOVA repeated measurements test.</AbstractText>Baseline left ventricle ejection fraction (LVEF) was poorer in group with AF (mean LVEF for group A: 20.9%, for group S: 26.4%, p=0.04). Baseline diastolic parameters were equally impaired. After infusion, diastolic parameters like velocity of propagation (Vp) and isovolumic relaxation time (IVRT) improved almost to same extent in both groups but deceleration time (DT) did not. IVRT values decreased (p=0.012) both in group S (from 108.6+/-23.2 msec to 100.4+/-28.4 msec) and group A (from 117.3+/-25.1 msec to 92.0+/-20.9 msec) without a significant difference between groups (p=0.180 for interaction). Another valuable diastolic parameter, Vp was also similarly improved (p=0.01) in both groups to similar extent (for group A, from 35.4+/-8.8 cm/sec to 41.1+/-7.7 cm/sec, for group S, from 33.7+/-7.5 cm/sec to 37.8+/-7.6 cm/sec; p=0.498 for interaction).</AbstractText>We have shown that in patients with chronic HF and AF, levosimendan improves left ventricular systolic and diastolic functions as good as those with HF and sinus rhythm. We suggest that a positive electrophysiological effect of levosimendan on failing myocardial tissue seems to fill the absence of atrial booster in patients with AF who are on beta-blocker therapy.</AbstractText> |
5,378 | [Quality of records in OMI-AP of the patients with stroke followed in primary care]. | 1) To determine the level of registration and control of cardiovascular risk factors in stroke patients treated in primary care in Murcia through electronic medical records. 2) To describe the registered drug treatment in patients with stroke.</AbstractText>Observational descriptive, retrospective, evaluated through the records in OMI (electronic medical records) in all areas of Murcia Health Service. A sample of 407 patients with stroke was analyzed. The analyzed variables were type of stroke, time of evolution, registered cardiovascular risk factors, registered cardiovascular disease, medication and degree of control of modifiable risk factors.</AbstractText>Cardiovascular risk factors recorded were hypertension (81.1%), dyslipemia (72.5%), diabetes (41.3%), abdominal obesity (22.9%) and tobacco (8.8%). Registered cardiovascular diseases were ischemic heart disease (22.1%), atrial fibrillation (13.8%), nephropathy (11.8%), myocardial infarction (5.7%) and left ventricular hypertrophy (3.4%). 2.5% (10) of patients met all criteria for good control. The LDL cholesterol was controlled (<100mg/dl) and recorded in 24.8% of patients and blood pressure in 41.3%. 78.1% of patients were being treated with antihypertensive drugs, 47.4% with lipid-lowering drugs, and 79.1% with antiplatelet or anticoagulant.</AbstractText>According to data recorded at OMI-AP the patients who have suffered a stroke have poor control of cardiovascular risk factors.</AbstractText>Copyright © 2010 SECA. Published by Elsevier Espana. All rights reserved.</CopyrightInformation> |
5,379 | Predictive value of preoperative tissue Doppler echocardiographic analysis for postoperative atrial fibrillation after pulmonary resection for lung cancer. | The objective of the present study was to evaluate the utility of tissue Doppler imaging for predicting the development of postoperative atrial fibrillation.</AbstractText>In this prospective observational study, we evaluated 126 patients with lung cancer who underwent a lobectomy during the 18-month period from August 2007 to January 2009. Preoperative evaluations for all patients included tissue Doppler imaging in addition to conventional echocardiographic analysis. The study end point was the development of postoperative atrial fibrillation.</AbstractText>Postoperative atrial fibrillation was identified in 29 (23%) patients, in whom significantly higher early transmitral velocity/tissue Doppler mitral annular early diastolic velocity values were noted compared with those seen in patients without atrial fibrillation (9.76 ± 2.3 vs 7.14 ± 1.7, P < .0001). The area under the receiver operating characteristic curve for early transmitral velocity/tissue Doppler mitral annular early diastolic velocity to predict postoperative atrial fibrillation after pulmonary resection for lung cancer was 0.83 (95% confidence interval, 0.74-0.92; P < .001). An early transmitral velocity/tissue Doppler mitral annular early diastolic velocity value of greater than 8 had a sensitivity of 90% and a specificity of 73% for predicting postoperative atrial fibrillation.</AbstractText>Postoperative atrial fibrillation after pulmonary resection might be associated with left ventricular diastolic dysfunction before surgical intervention revealed by using tissue Doppler imaging. Additional studies to establish the significance of tissue Doppler imaging as a tool to predict postoperative atrial fibrillation could contribute to improvements in lung cancer treatments.</AbstractText>Copyright © 2010 The American Association for Thoracic Surgery. All rights reserved.</CopyrightInformation> |
5,380 | Early repolarization, left ventricular diastolic function, and left atrial size in professional soccer players. | Recent data have suggested a relation among long-term endurance sport practice, left atrial remodeling, and atrial fibrillation. We investigated the influence of an increased vagal tone, represented by the early repolarization (ER) pattern, on diastolic function and left atrial size in professional soccer players. Fifty-four consecutive athletes underwent electrocardiography, echocardiography, and exercise testing as part of their preparticipation screening. Athletes were divided into 2 groups according to presence or absence of an ER pattern, defined as a ST-segment elevation at the J-point (STE) > or =0.1 mm in 2 leads. For linear comparisons average STE was calculated. Mean age was 24 +/- 4 years. Twenty-five athletes (46%) showed an ER pattern. Athletes with an ER pattern had a significant lower heart rate (54 +/- 9 vs 62 +/- 11 beats/min, p = 0.024), an increased E/e' ratio (6.1 +/- 1.2 vs 5.1 +/- 1.0, p = 0.002), and larger volumes of the left atrium (25.6 +/- 7.3 vs 21.8 +/- 5.0 ml/m(2), p = 0.031) compared to athletes without an ER pattern. There were no significant differences concerning maximum workload, left ventricular dimensions, and systolic function. Univariate regression analysis revealed significant correlations among age, STE, and left atrial volume. In a stepwise multivariate regression analysis age, STE and e' contributed independently to left atrial size (r = 0.659, p <0.001). In conclusion, athletes with an ER pattern had an increased E/e' ratio, reflecting a higher left atrial filling pressure, contributing to left atrial remodeling over time. |
5,381 | Continued breathing followed by gasping or apnea in a swine model of ventricular fibrillation cardiac arrest. | Continued breathing following ventricular fibrillation has here-to-fore not been described.</AbstractText>We analyzed the spontaneous ventilatory activity during the first several minutes of ventricular fibrillation (VF) in our isoflurane anesthesized swine model of out-of-hospital cardiac arrest. The frequency and type of ventilatory activity was monitored by pneumotachometer and main stream infrared capnometer and analyzed in 61 swine during the first 3 to 6 minutes of untreated VF.</AbstractText>During the first minute of VF, the air flow pattern in all 61 swine was similar to those recorded during regular spontaneous breathing during anesthesia and was clearly different from the patterns of gasping. The average rate of continued breathing during the first minute of untreated VF was 10 breaths per minute. During the second minute of untreated VF, spontaneous breathing activity either stopped or became typical of gasping. During minutes 2 to 5 of untreated VF, most animals exhibited very slow spontaneous ventilatory activity with a pattern typical of gasping; and the pattern of gasping was crescendo-decrescendo, as has been previously reported. In the absence of therapy, all ventilatory activity stopped 6 minutes after VF cardiac arrest.</AbstractText>In our swine model of VF cardiac arrest, we documented that normal breathing continued for the first minute following cardiac arrest.</AbstractText> |
5,382 | An observational study to assess changes in arterial blood gas values during untreated porcine ventricular fibrillation. | Cardiocerebral resuscitation (CCR) is reportedly superior to cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) even though active ventilation is not initially provided. Understandably, concerns have been raised regarding the withholding of positive pressure ventilation (PPV) during CCR because of the longstanding belief that respiratory gas exchange is a critical action during resuscitation.</AbstractText>In this observational study, we sought to quantify the effect of prolonged untreated ventricular fibrillation (VF) on arterial pH, partial pressure of carbon dioxide (pCO(2)), and partial pressure of oxygen (pO(2)) values in a swine model of witnessed cardiac arrest to begin exploring the validity of these concerns.</AbstractText>Both included studies were approved by the institutional animal care and use committee (IACUC). Eighty-three animals (25-35 kg) were instrumented under general anesthesia. Baseline characteristics were recorded. An arterial blood gas (ABG) sample was drawn from each animal via femoral catheter just prior to electrical induction of VF. After 8 minutes of untreated VF in one study (study 1 [n = 30]) and 10 minutes of untreated VF in the other study (study 2 [n = 53]), a second ABG sample was drawn. All samples were processed immediately using an i-STAT portable whole blood analyzer. Baseline characteristics of animals in the two studies were assessed using descriptive statistics. For the second ABG sample in each study, the mean pH, pCO(2), and pO(2) values, with 95% confidence intervals (95% CIs), were determined. The paired ABG results for each animal were then compared and the average pH, pCO(2), and pO(2) proportions, with 95% CIs, for each study were calculated.</AbstractText>The baseline characteristics of the animals in the two studies were similar. After 8 and 10 minutes of untreated VF cardiac arrest, the pH values were 7.35 (95% CI = 7.32, 7.37) and 7.37 (95% CI = 7.36, 7.38), the pCO(2) increased to 44.1 mmHg (95% CI = 41.1, 47.1) and 52.7 mmHg (95% CI = 51.0, 54.4), and the pO(2) decreased to 44.8 mmHg (95% CI = 42.2, 47.4) and 45.5 mmHg (95% CI = 43.3, 47.6), respectively.</AbstractText>Using our swine model of witnessed cardiac arrest with prolonged untreated VF, the arterial pH remained essentially unchanged and the pCO(2) increased to 1.42 times baseline after 10 minutes, while almost half of the initial O(2) concentration in the blood at the beginning of resuscitation remained.</AbstractText> |
5,383 | Anti-tachycardia pacing degenerated fast ventricular tachycardia into undetectable life-threatening tachyarrhythmia in a patient with non-ischemic dilated cardiomyopathy. | A 45-year-old man with dilated cardiomyopathy was admitted to our hospital due to congestive heart failure (CHF). Despite the optimal medical treatment, his condition had not improved because of severe left ventricular dysfunction. Because he experienced non-sustained ventricular tachycardia (VT), a biventricular implantable cardioverter-defibrillator (Bi-V ICD) was implanted for reduction of dyssynchrony and primary prevention of lethal tachyarrhythmia. After discharge, he developed CHF and was transported to our hospital by ambulance. In the ambulance, monomorphic sustained VT with 200 bpm suddenly occurred. The ICD detected it as fast VT and anti-tachycardia pacing (ATP) was delivered. After the ATP therapy, RR intervals of VT became irregular and prolonged. Ventricular fibrillation-like electrical activity was recorded by a far-field electrogram from the defibrillator, but the tachycardia cycle length exceeded 400 ms which is under the tachycardia detection rate. The device failed to deliver a shock and the patient had to be rescued with an external shock. This is a rare case of fast VT that degenerated into undetectable life-threatening tachyarrhythmia by ATP. |
5,384 | The effect of early and intensive statin therapy on ventricular premature beat or non-sustained ventricular tachycardia in patients with acute coronary syndrome. | Our study's aim was to evaluate the prognostic value of early and intensive lipid-lowering treatment on ventricular premature beat or non-sustained ventricular tachycardia (NSVT) after acute coronary syndrome (STEMI, non-STEMI, and unstable angina pectoris).</AbstractText>Some 586 patients with acute coronary syndrome were randomly divided into two groups: Group A (with conventional statin therapy, to receive 10 mg/day atorvastatin, n = 289) and Group B (given early and intensive statin therapy, 60 mg immediately and 40 mg/day atorvastatin, n = 297). The frequency of ventricular premature beat and NSVT was recorded via Holter monitoring after hospitalization (24 h and 72 h).</AbstractText>Seventy seven (11.8%) patients had NSVT. When compared to patients with no documented NSVT, patients with NSVT were older and more frequently had myocardial infarction in their history, diabetes mellitus, atrial fibrillation and an ejection fraction < 40%. Ventricular premature beats decreased significantly in the early and aggressive treatment group (24 h, p < 0.01; 72 h, p < 0.001). A significant reduction in NSVT was seen in the early and aggressive treatment group (24 h, p < 0.01; 72 h, p < 0.001). There were no side effects observed in either group.</AbstractText>Early and intensive lipid-lowering treatment can clearly decrease ventricular premature beats and NSVT.</AbstractText> |
5,385 | Cardiac arrhythmia and thyroid dysfunction: a novel genetic link. | Inherited Long QT Syndrome (LQTS), a cardiac arrhythmia that predisposes to the often lethal ventricular fibrillation, is commonly linked to mutations in KCNQ1. The KCNQ1 voltage-gated K(+) channel α subunit passes ventricular myocyte K(+) current that helps bring a timely end to each heart-beat. KCNQ1, like many K(+) channel α subunits, is regulated by KCNE β subunits, inherited mutations in which also associate with LQTS. KCNQ1 and KCNE mutations are also associated with atrial fibrillation. It has long been known that thyroid status strongly influences cardiac function, and that thyroid dysfunction causes abnormal cardiac structure and rhythm. We recently discovered that KCNQ1 and KCNE2 form a thyroid-stimulating hormone-stimulated K(+) channel in the thyroid that is required for normal thyroid hormone biosynthesis. Here, we review this novel genetic link between cardiac and thyroid physiology and pathology, and its potential influence upon future therapeutic strategies in cardiac and thyroid disease. |
5,386 | Prognostic significance of myocardial fibrosis in hypertrophic cardiomyopathy. | We investigated the significance of fibrosis detected by late gadolinium enhancement cardiovascular magnetic resonance for the prediction of major clinical events in hypertrophic cardiomyopathy (HCM).</AbstractText>The role of myocardial fibrosis in the prediction of sudden death and heart failure in HCM is unclear with a lack of prospective data.</AbstractText>We assessed the presence and amount of myocardial fibrosis in HCM patients and prospectively followed them for the development of morbidity and mortality in patients over 3.1 +/- 1.7 years.</AbstractText>Of 217 consecutive HCM patients, 136 (63%) showed fibrosis. Thirty-four of the 136 patients (25%) in the fibrosis group but only 6 of 81 (7.4%) patients without fibrosis reached the combined primary end point of cardiovascular death, unplanned cardiovascular admission, sustained ventricular tachycardia or ventricular fibrillation, or appropriate implantable cardioverter-defibrillator discharge (hazard ratio [HR]: 3.4, p = 0.006). In the fibrosis group, overall risk increased with the extent of fibrosis (HR: 1.18/5% increase, p = 0.008). The risk of unplanned heart failure admissions, deterioration to New York Heart Association functional class III or IV, or heart failure-related death was greater in the fibrosis group (HR: 2.5, p = 0.021), and this risk increased as the extent of fibrosis increased (HR: 1.16/5% increase, p = 0.017). All relationships remained significant after multivariate analysis. The extent of fibrosis and nonsustained ventricular tachycardia were univariate predictors for arrhythmic end points (sustained ventricular tachycardia or ventricular fibrillation, appropriate implantable cardioverter-defibrillator discharge, sudden cardiac death) (HR: 1.30, p = 0.014). Nonsustained ventricular tachycardia remained an independent predictor of arrhythmic end points after multivariate analysis, but the extent of fibrosis did not.</AbstractText>In patients with HCM, myocardial fibrosis as measured by late gadolinium enhancement cardiovascular magnetic resonance is an independent predictor of adverse outcome. (The Prognostic Significance of Fibrosis Detection in Cardiomyopathy; NCT00930735).</AbstractText>Copyright © 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,387 | A case of fulminant myocarditis associated with novel N1H1 influenza successfully treated by percutaneous cardiopulmonary support system. | We report a case of fulminant myocarditis associated with N1H1 influenza virus infection. N1H1 was confirmed by a polymerase chain reaction assay and she was treated with oseltamivir phosphate. She was admitted to the hospital because of respiratory distress, however, echocardiography revealed severely depressed wall motion followed by refractory ventricular fibrillation. Extracorporeal circulation by emergent percutaneous cardiopulmonary support system was required to maintain hemodynamic stability. Cardiac function was spontaneously and gradually restored within a week. Findings from biopsy samples taken on day 1 and day 23 were consistent with acute myocarditis. |
5,388 | Atrial pacing or ventricular backup-only pacing in implantable cardioverter-defibrillator patients. | The need for pacing support in typical ICD patients is unknown.</AbstractText>This study sought to determine whether atrial pacing with ventricular backup pacing is equivalent to ventricular backup pacing only in implantable cardioverter-defibrillator (ICD) patients.</AbstractText>We randomized 1,030 patients from 84 sites with indications for ICDs, with sinus rhythm, and without symptomatic bradycardia to atrial pacing with ventricular backup at 60 beats/min (518) or ventricular backup pacing at 40 beats/min (512). The primary end points were time to death, heart failure hospitalization (HFH), and heart failure-related urgent care (HFUC).</AbstractText>Follow-up was 2.4 ± 0.8 years when the trial was stopped for futility. There were 355 end point events (103 deaths, 252 HFH/HFUC) in 194 patients favoring ventricular backup pacing (event-free rate 77.7% vs. 80.3% for atrial pacing at 30 months; hazard ratio 1.14, upper confidence bound 1.59, prespecified noninferiority threshold 1.21), therefore equivalence between pacing arms was not demonstrated. Overall HFH/HFUC rates were slightly higher during atrial pacing (event-free rate 85.4% vs. 86.4% for ventricular backup pacing). Exploratory analyses revealed that the difference in HFH/HFUC rates was largely seen in patients with a PR interval ≥230 ms. There were no differences between groups for atrial fibrillation, ventricular tachycardia/ventricular fibrillation, quality of life, or echocardiographic measurements. Fewer patients in the atrial pacing group were reported to develop an indication for bradycardia pacing (3.7% vs. 7.3%, P = .0053).</AbstractText>Equivalence between atrial pacing and ventricular backup pacing only could not be demonstrated.</AbstractText>NCT00281099.</AbstractText>Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,389 | Effect of continuous compressions and 30:2 cardiopulmonary resuscitation on global ventilation/perfusion values during resuscitation in a porcine model. | Rescue ventilations during bystander resuscitation, although previously considered essential, interrupt the continuity of chest compressions and might have deleterious effects in basic life support. This study was undertaken to analyze the global ventilation/perfusion values of continuous compressions and 30:2 cardiopulmonary resuscitation to determine the effectiveness for each approach in a porcine model of prolonged bystander cardiopulmonary resuscitation for ventricular fibrillation.</AbstractText>Prospective, randomized animal study.</AbstractText>A university animal research laboratory.</AbstractText>Twenty-four male domestic pigs (n = 12/group) weighing 30 ± 2 kg.</AbstractText>All animals had ventricular fibrillation induced by programmed electrical stimulation instruments and were randomized into two groups. Continuous compressions or 30:2 compression/rescue ventilation cardiopulmonary resuscitation was performed in each group.</AbstractText>Continuous respiratory variables, hemodynamic parameters, and blood gas analysis outcomes were recorded, and global ventilation/perfusion values were calculated. Alveolar minute volume and global ventilation/perfusion values decreased progressively after ventricular fibrillation, but cardiac output was stable. The global ventilation/perfusion value was higher in the ventilation cardiopulmonary resuscitation group than that in the continuous compression group (p < .0001) and was higher than normal. Coronary perfusion pressure was progressively decreased after 6 mins of cardiopulmonary resuscitation and greatly fluctuated in the ventilation cardiopulmonary resuscitation group. Coronary perfusion pressure was higher in the continuous compression group than that in the ventilation cardiopulmonary resuscitation group after 9 mins of cardiopulmonary resuscitation (p < .05). Values for pH and Pao2 progressively decreased, but there were no significant differences between the two groups, except for pH at 12 mins of cardiopulmonary resuscitation and Paco2 after 3 mins of cardiopulmonary resuscitation.</AbstractText>In the first 12 mins of cardiopulmonary resuscitation, continuous compressions could maintain relatively better coronary perfusion pressure, Pao2, and global ventilation/perfusion values than 30:2 cardiopulmonary resuscitation. Therefore, rescue ventilation during 12 mins of simulated bystander cardiopulmonary resuscitation did not improve hemodynamics or outcomes compared with compression-only cardiopulmonary resuscitation.</AbstractText> |
5,390 | Impact of angiotensin-converting enzyme-inhibitors and angiotensin receptor blockers on long-term outcome of catheter ablation for atrial fibrillation. | We hypothesized that modulation of the renin-angiotensin-aldosterone system (RAAS) improves success following catheter ablation for atrial fibrillation (AF).</AbstractText>We examined a prospective registry of consecutive patients undergoing catheter ablation of paroxysmal or persistent AF between November 2004 and December 2008. Patients were divided based on whether they were taking RAAS modulators at the time of their first procedure and examined on an intention to treat basis. There were 419 patients (222 paroxysmal and 197 persistent AF) who underwent 1.8 ± 0.9 procedures. Median follow-up from the last procedure was 1.7 (range 0.9-5.0) years. There were 142 patients on RAAS modulators; they were older, more likely to suffer from hypertension, diabetes, coronary disease, or left ventricular impairment. Overall, sinus rhythm was maintained in 73.2% of those taking RAAS modulators vs. 77.6% of those taking none (P = 0.304). Multivariate analysis showed no impact of RAAS modulators [hazard ratios (HR): 1.97, CI: 0.56-6.89, P = 0.290] but also no effect of hypertension, ischaemic heart disease, left ventricular impairment, or diabetes that should have confounded results (persistent AF was found to predict failure; HR: 0.34, CI: 0.14-0.84, P = 0.020). Subgroup analysis of patients with risk factors for developing AF (hypertension, coronary artery disease, left ventricular impairment, or diabetes) found no benefit in this context, with sinus rhythm maintained in 73.2% of those taking RAAS modulators compared with 69.9% of those taking none (P = 0.574).</AbstractText>Modulation of the RAAS does not appear to affect maintenance of sinus rhythm following catheter ablation of AF.</AbstractText> |
5,391 | Premature coronary artery disease in a patient with glycogen storage disease III. | The glycogen storage diseases are a rare form of inherited metabolic disease affecting intracellular glycogen metabolism, and several studies suggest glycogen storage disease (GSD) III predisposes patients to dyslipidemia and endothelial dysfunction. The presence of premature atherosclerotic heart disease in patients with GSD III has not been reported in the literature. We report a case of a 24- year old patient with GSD III admitted with ventricular fibrillation cardiac arrest in the setting of anterior wall myocardial infarction. Further studies are warranted on the prevalence of atherosclerotic heart disease, and potential screening and preventative strategies, in this population of patients potentially at-risk for early cardiac events. |
5,392 | Induction of therapeutic hypothermia by paramedics after resuscitation from out-of-hospital ventricular fibrillation cardiac arrest: a randomized controlled trial. | Therapeutic hypothermia is recommended for the treatment of neurological injury after resuscitation from out-of-hospital cardiac arrest. Laboratory studies have suggested that earlier cooling may be associated with improved neurological outcomes. We hypothesized that induction of therapeutic hypothermia by paramedics before hospital arrival would improve outcome.</AbstractText>In a prospective, randomized controlled trial, we assigned adults who had been resuscitated from out-of-hospital cardiac arrest with an initial cardiac rhythm of ventricular fibrillation to either prehospital cooling with a rapid infusion of 2 L of ice-cold lactated Ringer's solution or cooling after hospital admission. The primary outcome measure was functional status at hospital discharge, with a favorable outcome defined as discharge either to home or to a rehabilitation facility. A total of 234 patients were randomly assigned to either paramedic cooling (118 patients) or hospital cooling (116 patients). Patients allocated to paramedic cooling received a median of 1900 mL (first quartile 1000 mL, third quartile 2000 mL) of ice-cold fluid. This resulted in a mean decrease in core temperature of 0.8 degrees C (P=0.01). In the paramedic-cooled group, 47.5% patients had a favorable outcome at hospital discharge compared with 52.6% in the hospital-cooled group (risk ratio 0.90, 95% confidence interval 0.70 to 1.17, P=0.43).</AbstractText>In adults who have been resuscitated from out-of-hospital cardiac arrest with an initial cardiac rhythm of ventricular fibrillation, paramedic cooling with a rapid infusion of large-volume, ice-cold intravenous fluid decreased core temperature at hospital arrival but was not shown to improve outcome at hospital discharge compared with cooling commenced in the hospital.</AbstractText> |
5,393 | Metformin is associated with improved left ventricular diastolic function measured by tissue Doppler imaging in patients with diabetes. | To examine the association between selected glucose-lowering medications and left ventricular (LV) diastolic function in patients with diabetes.</AbstractText>Retrospective cohort study (years 2005-2008).</AbstractText>Echocardiograms of 242 patients with diabetes undergoing coronary angiography were analyzed. All patients had an LV ejection fraction (LVEF) ≥20% and were without atrial fibrillation, bundle branch block, valvular disease, or cardiac pacemaker. Patients were grouped according to the use of metformin (n=56), sulfonylureas (n=43), insulin (n=61), and combination treatment (n=82).</AbstractText>Mean age (66±10 years) and mean LVEF (45±11%) were similar across the groups. Mean isovolumic relaxation time (IVRT) was 66±31, 79±42, 69±23, and 66±29 ms in metformin, sulfonylureas, insulin, and combination treatment groups respectively (P=0.4). Mean early diastolic longitudinal tissue velocity (e') was 5.3±1.6, 4.6±1.6, 5.3±1.8, and 5.4±1.7 cm/s in metformin, sulfonylureas, insulin, and combination treatment groups (P=0.04). In adjusted linear regression models, the use of metformin was associated with a shorter IVRT (parameter estimate -9.9 ms, P=0.049) and higher e' (parameter estimate +0.52 cm/s, P=0.03), compared with no use of metformin. The effects of metformin were not altered by concomitant use of sulfonylureas or insulin (P for interactions >0.4).</AbstractText>The use of metformin is associated with improved LV relaxation, as compared with no use of metformin.</AbstractText> |
5,394 | [Mortality prognosis factors in heart failure in a cohort of North-West Spain. EPICOUR study]. | Heart failure (HF) is a serious health problem in Spain because it has a high mortality rate and causes considerable costs to the health-care system. This paper presents a study made in the Spanish province of Ourense to study the survival of patients with HF related to the ventricular function or other possible risk factors (RF) associated with the HF prognosis.</AbstractText>A prospective cohort study was performed, considering any patient hospitalized due to HF from 1 January 1999 to 31 December 2002 (5318 patients) who had undergone an echocardiography that showed systolic or diastolic dysfunction as potential participants (2387 patients). After at least 24 months of the index episode of hospitalization, a sample of 2384 patients was chosen by random sampling. The principal measurement was based on survival and the differences observed in the performance of the left ventricular ejection fraction, of functional class (FC) of HF and of other clinical and epidemiological characteristics. The Kaplan-Meier, log-rank and Cox tests were used.</AbstractText>Mean age of the patients 74.84 (range 36-95); 53.4% males and 56.5% first admission. The most common antecedent was arterial hypertension (HTA) (59.9%), followed by valvulopathy (41.9%) and heart disease (HD) (26.8%). A total of 44.3% of the patients had atrial fibrillation-flutter (AF). Global survival at 5 years was 47.9% and specific survival rate for HF was 74.8%. There were no significant differences in survival between patients with heart failure and preserved systolic function (HF-PSF) and those who suffered systolic dysfunction (p=0.248). Prognostic factors of mortality in patients with HF are: advanced functional class (class III-IV) prior to admission (Hazard ratio [HR] 5.37), deterioration of the glomerular filtration rate (GFR) (HR 0.98), hypoalbuminemia (HR 0.59), hyponatremia (HR 0.93) and hyperkalemia (HR 1.79). The Castelli index higher than 4.5 is in the limit of statistical significance.</AbstractText>Global survival rate observed at 5 years of research is similar to the results found in already-published papers. Specific survival rate for HF is lower and there are no differences in the survival rate with regard to the left ventricle ejection fraction (E(f)). However, we show that hypoalbuminemia, hyperkalemia and high Castelli index are important prognostic factors of mortality in patients with HF.</AbstractText>Copyright © 2009 Elsevier España, S.L. All rights reserved.</CopyrightInformation> |
5,395 | Cardiac arrest with "pseudo-Brugada" ECG pattern in the setting of a coronary artery anomaly. | A 36-year-old Hispanic man with no prior cardiac history presented with chest pain and then ventricular fibrillation requiring defibrillation after a physical altercation. His ECG on presentation to the emergency room was suggestive of Brugada syndrome, which later normalized. Cardiac catheterization revealed anomalous origin of right coronary artery from the left coronary cusp (coursing between the pulmonary artery and the aorta) for which he underwent surgical reimplantation, and subsequent pharmacological challenge test did not provoke reappearance of a Brugada ECG pattern. A review of literature on Brugada syndrome and anomalous origin of the coronary arteries is presented.  |
5,396 | Clinical effectiveness of pulmonary vein isolation for arrhythmic events in a patient with catecholaminergic polymorphic ventricular tachycardia. | An 18-year-old woman with catecholaminergic polymorphic ventricular tachycardia (CPVT) underwent pulmonary vein isolation (PVI) because of frequent and inappropriate shocks from an implantable cardioverter defibrillator (ICD) associated with atrial fibrillation (AF) with a rapid ventricular response. While the PVI did not completely suppress the AF induced by an isoproterenol infusion, the Holter monitor recordings demonstrated a major decrease in the clinical episodes of AF and ventricular tachyarrhythmias in association with a reduced high-frequency (HF) component and ratio of the low-frequency (LF) component power to the HF component (LF/HF) after the PVI. The PVI can decrease the substrates that trigger and maintain the AF when it involves a pulmonary vein origin, and may exert an additional effect on the sympathetic nerve input to the heart. The PVI may be an adjunctive therapy for CPVT cases with drug refractory AF causing inappropriate ICD discharges. |
5,397 | [Psychosomatic aspects of cardiac arrhythmias]. | Emotional stress facilitates the occurrence of cardiac arrhythmias including sudden cardiac death. The prevalence of anxiety and depression is increased in cardiac patients as compared to the normal population. The risk of cardiovascular mortality is enhanced in patients suffering from depression. Comorbid anxiety disorders worsen the course of cardiac arrhythmias. Disturbance of neurocardiac regulation with predominance of the sympathetic tone is hypothesized to be causative for this. The emotional reaction to cardiac arrhythmias is differing to a large extent between individuals. Emotional stress may result from coping with treatment of cardiac arrhythmias. Emotional stress and cardiac arrhythmias may influence each other in the sense of a vicious circle. Somatoform cardiac arrhythmias are predominantly of psychogenic origin. Instrumental measures and frequent contacts between physicians and patients may facilitate disease chronification. The present review is dealing with the multifaceted relationships between cardiac arrhythmias and emotional stress. The underlying mechanisms and corresponding treatment modalities are discussed. |
5,398 | [In-hospital resuscitation concept with first-responder defibrillation. 2-year experience]. | Sudden cardiac arrest appears in 1-5 patients/ 1,000 clinical admissions. In spite of different research approaches, the prognosis after in-hospital resuscitation has not significantly improved in the last 40 years. This account presents the experiences with a hospital-wide emergency plan using the concept of defibrillation by first responders.</AbstractText>In 2003, a hospital-wide emergency plan was implemented. The concept comprised the setup of 15 "defibrillator points", training of the entire hospital personnel as first responder, and the introduction of an emergency team. Over the following 3 years, the concept was optimized. In a period from May 2006 to April 2008, the data of all patients who received an in-hospital resuscitation were collected.</AbstractText>Within 24 months, a total of 41 resuscitations were conducted. Out of these, 24 patients (58%) were under intensive monitoring when the event occurred. Initially, 15 patients (36%) showed ventricular fibrillation, 15 (36%) a pulseless electrical activity, and eleven (27%) an asystoly. A total of twelve patients (29%) left hospital alive. About half of them (42%) experienced ventricular fibrillation and were under observation at the time of event.</AbstractText>The data collected since the implementation of the hospital- wide emergency plan in 2003 reflect the daily clinical routine. The results show that there is a better outcome especially in patients with ventricular fibrillation when receiving first-responder defibrillation.</AbstractText> |
5,399 | Acute amiodarone promotes drift and early termination of spiral wave re-entry. | Intravenous application of amiodarone is commonly used in the treatment of life-threatening arrhythmias, but the underlying mechanism is not fully understood. The purpose of the present study is to investigate the acute effects of amiodarone on spiral wave (SW) re-entry, the primary organization machinery of ventricular tachycardia/fibrillation (VT/VF), in comparison with lidocaine. A two-dimensional ventricular myocardial layer was obtained from 24 Langendorff-perfused rabbit hearts, and epicardial excitations were analyzed by high-resolution optical mapping. During basic stimulation, amiodarone (5 microM) caused prolongation of action potential duration (APD) by 5.6%-9.1%, whereas lidocaine (15 microM) caused APD shortening by 5.0%-6.4%. Amiodarone and lidocaine reduced conduction velocity similarly. Ventricular tachycardias induced by DC stimulation in the presence of amiodarone were of shorter duration (sustained-VTs >30 s/total VTs: 2/58, amiodarone vs 13/52, control), whereas those with lidocaine were of longer duration (22/73, lidocaine vs 14/58, control). Amiodarone caused prolongation of VT cycle length and destabilization of SW re-entry, which is characterized by marked prolongation of functional block lines, frequent wavefront-tail interactions near the rotation center, and considerable drift, leading to its early annihilation via collision with anatomical boundaries. Spiral wave re-entry in the presence of lidocaine was more stabilized than in control. In the anisotropic ventricular myocardium, amiodarone destabilizes SW re-entry facilitating its early termination. Lidocaine, in contrast, stabilizes SW re-entry resulting in its persistence. |
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