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5,900 | [Plasma endothelin level in hypertensive patients receiving standard anti-hypertensive therapy with or without statins]. | To observe the association between plasma endothelin (ET) concentration and blood pressure level in essential hypertensive (EH) patients with or without complications and possible impact of statins on ET concentration.</AbstractText>From Sep 2007 to Mar 2009, 149 patients with EH were analyzed [44 EH, 40 EH complicated by left ventricular hypertrophy (EH-LVH), 36 EH complicated by atrial fibrillation (EH-AF), and 29 EH complicated by lacunar infarction (EH-LI)], 30 healthy persons were selected as controls. EH patients were randomly divided into routine treatment group (calcium antagonists, ACEI, diuretics, beta-receptor blocker for 8 weeks) and simvastatin intervention group (routine treatment + simvastatin 40 mg/d for 8 weeks), plasma ET concentrations before and after drug intervention were measured.</AbstractText>(1) ET concentration was higher in EH group than that in control group [(71.42 +/- 6.62) pg/ml vs. (45.52 +/- 8.28) pg/ml, P < 0.01]. ET concentration was higher in EH-LVH group, EH-AF group and EH-LI group than that in EH group [(97.67 +/- 10.53) pg/ml, (102.15 +/- 12.96) pg/ml, (103.49 +/- 9.91) pg/ml vs. (71.42 +/- 6.62) pg/ml, P <0.01]. The degrees of elevated blood pressure was positively correlated with ET concentrations(all P < 0.001). (2) The left atrial diameters of EH-AF group were positively correlated with ET concentration (r = 0.684, P < 0.001). The left ventricular mass index of EH-LVH group were positively correlated with ET concentration (r = 0.545, P < 0.001). (3) The percentages of class 3 hypertension in EH-LVH group, EH-AF group and EH-LI group were higher than that in EH group (57.5%, 50.0%, 62.1% vs. 25.0%, all P < 0.05). (4) Blood pressure in class 3 hypertension patient treated with simvastatin decreased more significantly than that in routine treatment group (P < 0.05). (5) ET concentration of class 2 hypertension patient treated with simvastatin decreased significantly than that in routine treatment group (P < 0.05). ET concentrations of class 3 hypertension patient treated with simvastatin and routine treatment patient decreased significantly after treatment (P < 0.05), and the former was lower (P < 0.05).</AbstractText>The level of ET were positively correlated with the severity of EH. Simvastatin could decrease the ET levels of patients with EH and blood pressure levels of patients with class 3 hypertension. It suggested that therapeutic alliance of antihypertensive drugs and statins could be benefit to patients with EH.</AbstractText> |
5,901 | Recurrent left ventricular myxoma presenting as cerebrovascular accidents in a teenage girl. | Myxoma cordis is the most frequent primary cardiac tumour in adults. Paediatric primary cardiac tumours are rare, the most common type being rhabdomyoma. Atrial and ventricular myxomas occur infrequently in the paediatric age group. Intracardiac myxomas are seen with an estimated incidence of 0.5 per million population per year. Approximately 70% of the affected patients are of female gender. Recurrences are rare (1.3%). Asymptomatic recurrences are observed in young patients who have a familial history of tumour or multifocal myxomas. Although rare, cardiac aetiology (atrial fibrillation, intracardiac thrombi, patent foramen ovale, myxoma, endocarditis) should be considered. In children presenting with central neurological symptoms, a cardiac aetiology has to be considered. We describe a rare case of an 18-year-old girl presenting with a recurrent left ventricular myxoma, accompanied by neurological deficits. |
5,902 | Atrial electroanatomical remodeling as a determinant of different outcomes between two current ablation strategies: circumferential pulmonary vein isolation vs pulmonary vein isolation. | The purpose of this study was to investigate the relationship between the efficacy of the 2 different ablation techniques of atrial fibrillation (AF) and left atrial (LA) size.</AbstractText>A total of 81 patients with paroxysmal AF (n = 58) or persistent AF (n = 23) refractory to antiarrhythmic drugs underwent circumferential pulmonary vein isolation (PVI; n = 45) or PVI (n = 36) without respect to echocardiographic results for LA volume index (LAVI). Of the 81 patients, 41 had less dilated LA (group 1; LAVI < 27 cc/m(2)) and 40 had dilated LA (group 2; LAVI > or = 27 cc/m(2)). During the 9-month follow-up, 33 patients (73.3%) after circumferential PVI and 18 (50%) after PVI (P = .031) were free of arrhythmia. The risk of recurrence was associated with persistent AF, hypertension, LAVI > 27 ml/m(2), PVI, early recurrence of AF, and lower left ventricular (LV) ejection fraction (all P value <.05). In the univariate analysis of each group, PVI (hazard ratio [HR]: 2.92, 95% confidence interval [CI]: 0.12-7.08, P = .018) was associated with late recurrence only in group 2. Cox regression analysis also showed that PVI (HR: 5.6, 95% CI: 1.9-16.56, P = .002) was a significant independent predictor of recurrence only in group 2.</AbstractText>Circumferential PVI is more effective than PVI only in patients with a structural change of the atria, that is, a dilated LA. Our study suggests that a successful outcome in dilated LA may depend on wide modification of LA electroanatomical substrates, but wide ablation in less dilated LA may be unnecessary. Different technical strategies according to LA size are required for more a effective outcome.</AbstractText>Copyright (c) 2009 Wiley Periodicals, Inc.</CopyrightInformation> |
5,903 | Recent advances in the pharmacological treatment of cardiac arrythmias. | Atrial and ventricular arrhythmias are associated with substantial morbidity and mortality and thus are a significant economic burden for healthcare systems. Currently available pharmacological agents have limited efficacy or the risk of relevant side effects, such as drug toxicity and proarrhythmic potential. Recent scientific developments have added new aspects and approaches to this field meriting a fresh review of treatment options. These include novel ion-channel blockers (e.g. dronedarone, celivarone, vernakalant, ranolazine), non-ion channel blockers (e.g. GsMtx4) such as gap junction modulators (rotigaptide) and drugs antagonizing the angiotensin system (ACE-inhibitors, angiotensin II receptor blockers), which appear to have various effects on cardiac electrophysiology. Special emphasis is placed on new antiarrhythmic drugs (e.g. dantrolene) targeting molecular, proarrhythmogenic and structural remodeling. Finally, new developments in the prevention of thromboembolic complications of atrial fibrillation are discussed (dabigatran). |
5,904 | Ganglionic plexus ablation during pulmonary vein isolation--predisposing to ventricular arrhythmias? | Catheter ablation is increasingly used to treat patients with atrial fibrillation (AF). Ablation of ganglionic plexi is often performed to reduce vagal innervation and has been shown to confer a better long-term outcome in terms of AF recurrence. We report a case of a patient having AF ablation with a profound vagal response, suggesting ganglionic plexus ablation, who subsequently developed ventricular fibrillation after programmed ventricular stimulation. Reduced vagal modulation is known to predispose to ventricular arrhythmias and vagal denervation following AF ablation may predispose to ventricular arrhythmias and requires further study. |
5,905 | Congenital short QT syndrome. | The Short QT Syndrome is a recently described new genetic disorder, characterized by abnormally short QT interval, paroxysmal atrial fibrillation and life threatening ventricular arrhythmias. This autosomal dominant syndrome can afflict infants, children, or young adults; often a remarkable family background of cardiac sudden death is elucidated. At electrophysiological study, short atrial and ventricular refractory periods are found, with atrial fibrillation and polymorphic ventricular tachycardia easily induced by programmed electrical stimulation. Gain of function mutations in three genes encoding K(+) channels have been identified, explaining the abbreviated repolarization seen in this condition: KCNH2 for I(kr) (SQT1), KCNQ1 for I(ks) (SQT2) and KCNJ2 for I(k1) (SQT3). The currently suggested therapeutic strategy is an ICD implantation, although many concerns exist for asymptomatic patients, especially in pediatric age. Pharmacological treatment is still under evaluation; quinidine has shown to prolong QT and reduce the inducibility of ventricular arrhythmias, but awaits additional confirmatory clinical data. |
5,906 | Fracture of epicardial resynchronization lead caused by deceleration injury. | A 50-year-old man with heart failure, systolic dysfunction, and abnormal septal motion underwent ventricular resynchronization. Postoperative clinical and echocardiographic improvement was observed. Several months later, he complained of worsening functional class after a traffic accident. Pacing lead fracture was diagnosed. After replacing the lead, improvement of clinical condition and ventricular parameters was achieved. The role of seat belts in causing dysfunction of pacemakers and resynchronization devices after deceleration injury is discussed. |
5,907 | Imaging and atrial fibrillation: the role of multimodality imaging in patient evaluation and management of atrial fibrillation. | Atrial fibrillation (AF) is the most common cardiac arrhythmia, and is associated with an increased risk of cardiac morbidity and mortality. In this review, the role of multimodality imaging in the evaluation and treatment of AF is discussed in two main parts. First, an overview of the initial assessment of an AF patient is provided, including the role of different imaging techniques. Conditions that are associated with AF (coronary artery disease, heart failure, valvular heart disease, and left ventricular hypertrophy), and the assessment with various imaging modalities, will be reviewed. Furthermore, left atrial size assessment and the screening for thrombus formation are addressed. Secondly, the role of imaging in the invasive treatment of AF with catheter ablation is reviewed. Issues that should be considered before the procedure including contra-indications and pulmonary vein and left atrial anatomy will be discussed. Furthermore, the integration of different imaging modalities during catheter ablation is explored. Finally, an overview of the role of imaging in the follow-up of patients treated with catheter ablation will be provided. |
5,908 | A spontaneous Type 1 electrocardiogram pattern in lead V2 is an independent predictor of ventricular fibrillation in Brugada syndrome. | Risk stratification for Brugada syndrome remains controversial. We investigated the relationships between episodes of ventricular fibrillation (VF) and various clinical, electrocardiographic, electrophysiologic, and genetic parameters both retrospectively and prospectively.</AbstractText>Fifty-two patients with Brugada syndrome (49 men, average age 42 +/- 3 years) were studied. In the Brugada patients with a VF history, the frequency of a spontaneous Type 1 electrocardiogram (ECG) pattern in lead V2 was significantly higher and the STJ amplitude in the V1 and V2 leads was also higher than in those without a VF history. Multivariate analyses revealed that the spontaneous Type 1 ECG pattern in lead V2 (but not lead V1) was the only independent predictor of a VF history. During a mean follow-up period of 39 +/- 4 months, 38.8% of the patients with a VF history and 2.9% of those without experienced an appropriate implantable cardioverter-defibrillation owing to VF. A multivariate analysis using a Cox's proportional hazard model showed that a VF history and spontaneous Type 1 ECG pattern in lead V2 were independent predictors of subsequent VF events.</AbstractText>A spontaneous Type 1 Brugada ECG pattern in lead V2 (but not lead V1) was both a prospective and retrospective independent predictor of VF episodes in Brugada syndrome.</AbstractText> |
5,909 | Predictors of survival from out-of-hospital cardiac arrest: a systematic review and meta-analysis. | Prior studies have identified key predictors of out-of-hospital cardiac arrest (OHCA), but differences exist in the magnitude of these findings. In this meta-analysis, we evaluated the strength of associations between OHCA and key factors (event witnessed by a bystander or emergency medical services [EMS], provision of bystander cardiopulmonary resuscitation [CPR], initial cardiac rhythm, or the return of spontaneous circulation). We also examined trends in OHCA survival over time.</AbstractText>An electronic search of PubMed, EMBASE, Web of Science, CINAHL, Cochrane DSR, DARE, ACP Journal Club, and CCTR was conducted (January 1, 1950 to August 21, 2008) for studies reporting OHCA of presumed cardiac etiology in adults. Data were extracted from 79 studies involving 142 740 patients. The pooled survival rate to hospital admission was 23.8% (95% CI, 21.1 to 26.6) and to hospital discharge was 7.6% (95% CI, 6.7 to 8.4). Stratified by baseline rates, survival to hospital discharge was more likely among those: witnessed by a bystander (6.4% to 13.5%), witnessed by EMS (4.9% to 18.2%), who received bystander CPR (3.9% to 16.1%), were found in ventricular fibrillation/ventricular tachycardia (14.8% to 23.0%), or achieved return of spontaneous circulation (15.5% to 33.6%). Although 53% (95% CI, 45.0% to 59.9%) of events were witnessed by a bystander, only 32% (95% CI, 26.7% to 37.8%) received bystander CPR. The number needed to treat to save 1 life ranged from 16 to 23 for EMS-witnessed arrests, 17 to 71 for bystander-witnessed, and 24 to 36 for those receiving bystander CPR, depending on baseline survival rates. The aggregate survival rate of OHCA (7.6%) has not significantly changed in almost 3 decades.</AbstractText>Overall survival from OHCA has been stable for almost 30 years, as have the strong associations between key predictors and survival. Because most OHCA events are witnessed, efforts to improve survival should focus on prompt delivery of interventions of known effectiveness by those who witness the event.</AbstractText> |
5,910 | Improving outcome after out-of-hospital cardiac arrest by strengthening weak links of the local Chain of Survival; quality of advanced life support and post-resuscitation care. | Survival after out-of-hospital cardiac arrest (OHCA) depends on a well functioning Chain of Survival. We wanted to assess if targeted attempts to strengthen the weak links of our local chain; quality of advanced life support (ALS) and post-resuscitation care, would improve outcome.</AbstractText>Utstein data from all OHCAs in Oslo during three distinct 2-year time periods 1996-1998, 2001-2003 and 2004-2005 were collected. Before the second period the local ALS guidelines changed with increased focus on good quality chest compressions with minimal pauses, while standardized post-resuscitation care including goal directed therapy with therapeutic hypothermia and percutaneous coronary intervention was added in the third period. Additional a priori sub-group analyses of arrests with cardiac aetiology as well as bystander witnessed ventricular fibrillation/tachycardia (VF/VT) arrests with cardiac aetiology were performed.</AbstractText>ALS was attempted in 454, 449, and 417 patients with OHCA in the first, second and last time period, respectively. From the first to the third period VF/VT arrests declined (40% vs. 33%, p=0.039) and fewer arrests were witnessed (80% vs. 72%, p=0.022) and response intervals increased (7+/-4 to 9+/-4 min, p<0.001). Overall survival increased from 7% (first period) to 13% (last period), p=0.002, and survival in the sub-group of bystander witnessed VF/VT arrests with cardiac aetiology increased from 15% (first period) to 35% (last period), p=0.001.</AbstractText>Survival after OHCA was increased after improving weak links of our local Chain of Survival, quality of ALS and post-resuscitation care.</AbstractText>Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,911 | Transthoracic defibrillation potential gradients in a closed chest porcine model of prolonged spontaneous and electrically induced ventricular fibrillation. | The purpose of this study was to measure the local electrical field or potential gradient, measured with a catheter-based system, required to terminate long duration electrically or ischaemically induced ventricular fibrillation (VF). We hypothesized that prolonged ischaemic VF would be more difficult to terminate when compared to electrically induced VF of similar duration.</AbstractText>Thirty anesthetized and instrumented swine were randomized to electrically induced VF or spontaneous, ischaemically induced VF, produced by balloon occlusion of the left anterior descending coronary artery. After 7 min of VF, chest compressions were initiated and rescue shocks were attempted 1 min later. The potential gradient for each shock was measured and the mean values required for defibrillation compared for the VF groups.</AbstractText>The number of shocks and the shock strength required for termination of VF were not significantly different for the groups. The potential gradient of the first successful defibrillating shock was significantly greater in the spontaneous, occlusion-induced VF group (12.80+/-2.82 V/cm vs 9.60+/-2.48 V/cm, p=0.002). The number of refibrillations was greater in the ischaemic group than in the non-ischaemic electrical group (6+/-4 vs 1+/-1, p<0.001). The number of animals requiring a shock at 360J was 2.5 times greater for the ischaemic group.</AbstractText>Defibrillation of prolonged VF produced by acute myocardial ischaemia requires a significantly greater potential gradient to terminate than prolonged VF induced by electrical stimulation of the right ventricular endocardium. The VF duration used in this study approximates that occurring in victims of out-of-hospital cardiac arrest. Our findings may be of clinical importance in the management of such patients.</AbstractText>Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,912 | Discriminating the effect of accelerated compression from accelerated decompression during high-impulse CPR in a porcine model of cardiac arrest. | Piston based mechanical chest compression devices deliver compressions and decompressions in an accelerated pattern, resulting in superior haemodynamics compared to manual compression in animal studies. The present animal study compares haemodynamics during two different hybrid compression patterns to a standard compression pattern resembling that of modern mechanical chest compression devices.</AbstractText>In 12 anaesthetized domestic pigs in ventricular fibrillation, coronary perfusion pressures (CPP) and cerebral cortical blood flow (CCBF) was measured, and transesophageal echocardiography (TEE) was performed. Two hybrid compression patterns, one with accelerated trapezoid compression and slower sinusoid decompression (TrS), and one with slower sinusoid compression and accelerated trapezoid decompression (STr), were tested against a standard accelerated trapezoid compression-decompression pattern (TrTr) in a cross-over randomised setup.</AbstractText>There were 7% (1, 14, p=0.046) lower CCBF and 3 mmHg (1, 5, p=0.017) lower CPP with the TrS compared to TrTr pattern. No significant difference between STr and TrTr pattern in either CCBF, 6% (-3, 15, p=0.176) or CPP, 0 mmHg (-2, 3, p=0.703) was present. Our TEE recordings were insufficient for haemodynamic comparison between the different compression-decompression patterns. Despite standardized sternal piston position and placement of the pigs, TEE revealed varying degree of asymmetrical heart chamber compression in the animals.</AbstractText>Both cardiac and cerebral perfusion benefited from accelerated decompression, while accelerated compression did not improve haemodynamics. The evolution of mechanical CPR is dependent on further research on mechanisms generating forward blood flow during external chest compressions.</AbstractText>Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,913 | Efficacy of a novel bipolar radiofrequency ablation device on the beating heart for atrial fibrillation ablation: a long-term porcine study. | Over recent years, a variety of energy sources have been used to replace the traditional incisions of the Cox maze procedure for the surgical treatment of atrial fibrillation. This study evaluated the safety and efficacy of a new bipolar radiofrequency ablation device for atrial ablation in a long-term porcine model.</AbstractText>Six pigs underwent a Cox maze IV procedure on a beating heart off cardiopulmonary bypass using the AtriCure Isolator II bipolar ablation device (AtriCure, Inc, Cincinnati, Ohio). In addition, 6 pigs underwent median sternotomy and pericardiotomy alone to serve as a control group. All animals were allowed to survive for 30 days. Each pig underwent induction of atrial fibrillation and was then humanely killed to remove the heart en bloc for histologic assessment. Magnetic resonance imaging scans were also obtained preoperatively and postoperatively to assess atrial and ventricular function, pulmonary vein anatomy, valve function, and coronary artery patency.</AbstractText>All animals survived the operation. Electrical isolation of the left atrial appendage and the pulmonary veins was documented by pacing acutely and at 30 days in all animals. No animal that underwent the Cox maze IV procedure was able to be induced into atrial fibrillation at 30 days postoperatively, compared with all the sham animals. All 257 ablations examined were discrete, linear, and transmural, with a mean lesion width of 2.2 +/- 1.1 mm and a mean lesion depth of 5.3 +/- 3.0 mm.</AbstractText>The AtriCure Isolator II device was able to create reliable long-term transmural lesions of the modified Cox maze procedure on a beating heart without cardiopulmonary bypass 100% of the time. There were no discernible effects on ventricular or valvular function.</AbstractText>2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,914 | Clinical characteristics and outcomes of heart failure with preserved ejection fraction: lessons from epidemiological studies. | Recent epidemiological studies have demonstrated that nearly half of all patients with heart failure (HF) have preserved left ventricular ejection fraction (HFPEF). Compared to those with reduced EF, patients with HFPEF are older, more likely to be women, less likely to have coronary artery disease, and more likely to have hypertension and atrial fibrillation. Patients with HFPEF receive different pharmacological as well as nonpharmacological treatments from those with reduced EF. Morbidity and mortality in patients with HFPEF are largely similar to those with reduced EF. Although much information has recently been obtained about the clinical characteristics, medications, and outcomes of HFPEF by large-scale clinical and epidemiological studies, effective management strategies need to be established for this type of HF. |
5,915 | Catheter ablation of atrial fibrillation guided by complex fractionated atrial electrogram mapping of atrial fibrillation substrate. | Cardiologists and physicians have witnessed a significant change in the management of atrial fibrillation (AF): antiarrhythmic agents are no longer considered more effective than just merely using compounds that control ventricular response of the arrhythmia with anticoagulation in high-risk patients. Catheter ablation has grown into wider acceptance as an important therapeutic modality in treating tachyarrhythmias. And over the past decade, several studies have clearly established that catheter ablation of atrial fibrillation is safe and effective and is an important alternative therapeutic option to the pharmacological approach. In general, there are two approaches to AF ablation: The anatomical approach, the most popular one, relies on isolation of electrical connections of all four pulmonary veins to the left atrium with or without adjuvant ablations, i.e. additional linear ablations. The second approach is the electrogram-guided approach by mapping and targeting areas of complex fractionated atrial electrograms (CFAE) which is the main topic of this review. The myriad pathologies leading to and resulting from AF have led to many theories regarding how substrate should be defined and how to reconcile substrate ablation with trigger ablation. The identification of spatiotemporally stable areas of very low amplitude short cycle length CFAE in a sea of otherwise discrete normal amplitude and relatively longer cycle length electrograms led to ablate the CFAE as a marker of abnormal substrate. This pure substrate-based ablation strategy has resulted in remarkable success, including mortality benefit, even in high-risk patients with very long standing persistent AF. In this review, we discuss in detail the prevailing mechanisms underlying CFAE, how to map and ablate CFAE sites, correlation of CFAE areas to those of ganglionic plexi, clinical outcomes of the approach, and the role of CFAE in the hybrid approach of AF ablation using a combination of pulmonary vein isolation and targeting CFAE areas. |
5,916 | Delayed thrombolysis in a patient presenting after 12 hours of chest pain, cardiogenic shock and life-threatening arrhythmias. | This 63 years old man presented to the emergency room with chest pain of more than 12 hours duration. The initial electrocardiogram showed as ST segment elevation inferior and right ventricular infarction. He developed signs and symptoms consistent with cardiogenic shock, followed by life threatening ventricular fibrillation and cardiac arrest. After repeated cardio-respiratory resuscitations and successful cardiac defibrillation, thrombolytic therapy was administered followed by clinical and hemodynamic improvements. One-week later cardiac catheterization and coronary arteriography were performed. The study showed 93% obstructive lesion in the proximal right coronary artery, an angioplasty was performed and a stent was placed. After appropriate re-adjustment of medical therapy, the patient was discharged and followed in the outpatient clinic. Although the time frame to administer thrombolytic therapy was over the 12 hours window as suggested by the AHA guidelines1, the potential risks benefits in the casepresented justifed the used of fibrinolytic therapy. Considering the multiple complications that the patient presented, fibrinolytic therapy needs to be considered even after 12 hours of symptoms initiation, particularly when facilities for primary percutaneous coronary interventions are not readily available. |
5,917 | [Stress cardiomyopathy, a topical cardiac disorder]. | Stress cardiomyopathy (Tako-Tsubo, Broken Heart syndrome, or apical ballooning syndrome) was recently recognized as a distinct clinical entity. The aims of this review are to define this acute and reversible cardiomyopathy and to list its major clinical, biological and angiographic features. We performed a Medline scan for all relevant case series. The studies thus identified suggest that the apical ballooning syndrome accounts for 2% of ST-elevation infarcts, mainly affects women, and occurs after major emotional or physical stress. Most patients present with chest pain and dyspnoea, cardiogenic shock and (or?) ventricular fibrillation. ST segment modifications and mildly elevated cardiac enzyme levels are reported in 81% of patients. Left ventricular dysfunction occurs in the absence of epicardial coronary artery obstruction and typically consists of a hyperkinetic basal region and an akinetic apical half of the ventricle. The in-hospital mortality rate is about 1.2%. Most patients recover fully after a few weeks. Norepinephrine concentrations are elevated in three-quarters of patients. This syndrome should be considered among the differential diagnoses in patients presenting with chest pain, and especially in post-menopausal women with a recent history of stress. In its broadest sense, this phenomenon may encompass a range of disorders, including left ventricular dysfunction following central nervous system injury. It should also be considered in women with acute coronary syndromes. |
5,918 | Current review of Brugada syndrome: from epidemiology to treatment. | Brugada syndrome is a genetic cause of sudden cardiac arrest characterized by abnormal electrocardiographic (ECG) pattern in the right precordial leads either at rest or after provocation. In this condition, sudden death may occur due to polymorphic ventricular tachycardia or ventricular fibrillation. In approximately 30% of patients, sudden cardiac arrest is the initial clinical manifestation of Brugada syndrome. Treatment strategies for Brugada syndrome are evolving. Currently, the implanted cardioverter defibrillator (ICD) is the only proven treatment for Brugada syndrome. Candidates for ICD include patients include those with the type 1 ECG pattern or who have been successfully resuscitated from sudden death or have had unexplained syncope. |
5,919 | Coupled pacing improves left ventricular function during simulated atrial fibrillation without mechanical dyssynchrony. | Electrical stimulation [coupled pacing (CP)] applied near the end of the T-wave is able to create a retrograde activation of the atrioventricular (AV) node in turn to prevent rapid ventricular conduction during atrial fibrillation (AF). The impact of this pacing modality associated with cardiac resynchronization therapy (CRT) has been evaluated in the present experimental study.</AbstractText>After inducing AF by rapid pacing in six dogs, we applied the following pacing modalities: rapid right ventricular (RV) pacing, rapid CRT, CRT with an additional RV paced beat (CP) at a specific delay (CRT + CP), and CRT with vagal stimulation (CRT-VS). Left ventricular (LV) pressure recordings and echocardiography for 2D strain analysis were performed. CRT + CP reduced the ventricular response rate and increased the LV systolic pressure and cardiac output compared with CRT alone (136 +/- 6 vs. 86 +/- 13 mmHg, P < 0.05 and 2.0 +/- 0.4 vs.1.2 +/- 0.1, P < 0.05 L/m, respectively). Compared with CRT-VS, CRT + CP increased the LV ejection fraction (LVEF = 51 +/- 10 vs. 28 +/- 4%, P < 0.05), peak global circumferential strain (-17 +/- 2 vs. -11 +/- 3%), and diastolic filling time (49 +/- 6 vs. 28 +/- 3%, P < 0.02) suggesting beneficial effects of CP beyond rate control. CRT + CP did not result in increased dyssynchrony [CRT (8.3 +/- 2%) vs. CRTCP (8.4 +/- 3%, P = NS)].</AbstractText>CRT + CP effectively reduces ventricular contractile rate and leads to an increase in systolic and diastolic performance without inducing mechanical dyssynchrony.</AbstractText> |
5,920 | The development of heart failure in patients with diabetes mellitus and pre-clinical diastolic dysfunction a population-based study. | The purpose of this study was to evaluate the outcomes of pre-clinical diastolic dysfunction in diabetic patients.</AbstractText>Studies have reported a high prevalence of pre-clinical diastolic dysfunction among patients with diabetes mellitus.</AbstractText>We identified all diabetic patients with a tissue Doppler imaging assessment of diastolic function in Olmsted County, Minnesota, from 2001 to 2007. Diastolic dysfunction was defined as a passive transmitral left ventricular (LV) inflow velocity to tissue Doppler imaging velocity of the medial mitral annulus during passive filling (E/e') ratio >15. The main outcome was the development of heart failure (HF). Secondary outcomes were the development of atrial fibrillation and death.</AbstractText>Overall, 1,760 diabetic patients with a tissue Doppler echocardiographic assessment of diastolic function were identified; 411 (23%) patients had diastolic dysfunction. Using multivariable Cox's proportional hazard modeling, we determined that for every 1-U increase in the passive transmitral LV inflow velocity to tissue Doppler imaging velocity of the medial mitral annulus during passive filling (E/e') ratio, the hazard ratio (HR) of HF increased by 3% (HR: 1.03; 95% confidence interval [CI]: 1.01 to 1.06; p = 0.006) and that diastolic dysfunction was associated with the subsequent development of HF after adjustment for age, sex, body mass index, hypertension, coronary disease, and echocardiographic parameters (HR: 1.61; 95% CI: 1.17 to 2.20; p = 0.003). The cumulative probability of the development of HF at 5 years for diabetic patients with diastolic dysfunction was 36.9% compared with 16.8% for patients without diastolic dysfunction (p < 0.001). Furthermore, diabetic patients with diastolic dysfunction had a significantly higher mortality rate compared with those without diastolic dysfunction.</AbstractText>We demonstrated that an increase in the passive transmitral LV inflow velocity to tissue Doppler imaging velocity of the medial mitral annulus during passive filling (E/e') ratio in diabetic patients is associated with the subsequent development of HF and increased mortality independent of hypertension, coronary disease, or other echocardiographic parameters.</AbstractText>Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,921 | A critical decrease in dominant frequency and clinical outcome after catheter ablation of persistent atrial fibrillation. | Termination of persistent atrial fibrillation (AF) by radiofrequency ablation (RFA) is associated with a high probability of freedom from AF but requires extensive ablation and long procedure times.</AbstractText>The purpose of this study was to determine whether a critical decrease in the dominant frequency (DF) of AF is a sufficient endpoint for RFA of persistent AF.</AbstractText>Antral pulmonary vein isolation (APVI) followed by RFA of complex fractionated atrial electrograms (CFAEs) in the atria and coronary sinus was performed in 100 consecutive patients with persistent AF. The DF of AF in lead V1 and in the coronary sinus was determined by fast Fourier transform (FFT) analysis at baseline and before termination of AF to identify a critical decrease in DF predictive of sinus rhythm after RFA.</AbstractText>A > or =11% decrease in DF had the highest accuracy in predicting freedom from atrial arrhythmias, with a sensitivity of 0.71 and a specificity of 0.82 (P <.001). At a mean follow-up of 14 +/- 3 months after one ablation procedure, sinus rhythm was maintained off antiarrhythmic drugs in 8/35 (23%) and 20/26 (77%) of patients with a <11% and > or =11% decrease in DF, respectively (P <.001). Sinus rhythm was maintained in 24/39 patients (62%) in whom RFA terminated AF. The duration of RFA and total procedure time were longer in patients with AF termination (95 +/- 23 and 358 +/- 87 minutes) than in patients with a <11% decrease in the DF (77 +/- 16 and 293 +/- 70 minutes) or > or =11% decrease in DF (80 +/- 17 and 289 +/- 73 minutes), respectively (P <.01). Among the variables of age, gender, left atrial diameter, duration of AF, left ventricular ejection fraction, duration of RFA, a > or =11% decrease in DF, and termination of AF, a > or =11% decrease in DF (odds ratio = 9.89, 95% confidence interval [CI] 2.84-34.47) and termination during RFA (OR = 4.38, 95% CI 1.50-12.80) were the only independent predictors of freedom from recurrent atrial arrhythmias.</AbstractText>In a retrospective analysis of consecutive patients with persistent AF, a decrease in the DF of AF by 11% in response to APVI and ablation of CFAEs was associated with a probability of maintaining sinus rhythm that was similar to that when RFA terminates AF.</AbstractText>Copyright 2009 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
5,922 | Cardiac manifestations of neuromuscular disorders in children. | Cardiac abnormalities occur in association with many of the neuromuscular disorders that present in childhood. Genetic defects involving the cytoskeleton, nuclear membrane, and mitochondrial function have all been described in patients with skeletal myopathy and cardiac involvement. The most common classes of neuromuscular disorders with cardiac manifestations are the muscular dystrophies- Duchenne, Becker, limb-girdle and Emery Dreifuss. Friedreich Ataxia and myotonic dystrophy also have important cardiac involvement. The type and extent of cardiac manifestations are specific to the type of neuromuscular disorder. The most common cardiac findings include dilated or hypertrophic cardiomyopathy, atrioventricular conduction defects, atrial fibrillation and ventricular arrhythmias. Screening for cardiac involvement should be performed in all children with neuromuscular disorders that have the potential for cardiac involvement. This review discusses the cardiac findings associated with specific neuromuscular disorders and outlines the indications for evaluation and treatment. |
5,923 | Successful cardiopulmonary resuscitation in pregnancy: a case report. | The management of cardiac arrest in pregnancy is an important task for the emergency physicians. The clinical outcome of mother or fetus will often depend on the successful resuscitation of the first few minutes. Furthermore, the resuscitation team leader should consider the necessity of emergency hysterotomy (cesarean delivery) as soon as a pregnant woman develops cardiac arrest. We report a case of a 28-year-old pregnant woman who had a ventricular fibrillation cardiac arrest. She was successfully resuscitated in our emergency department and a single male healthy infant was delivered via cesarean section at 36 weeks' gestation. Mother and baby were discharged survival and neurologically intact from the intensive care unit (ICU) on day 25. We emphasize that understanding the causes of cardiac arrest during pregnancy, its early recognition and prompt resuscitation by recent ACLS guidelines may decrease both maternal and fetal morbidity or mortality.</AbstractText>Cardiac arrest; Cardiopulmonary resuscitation; Cesarean delivery; Fetus; Pregnant.</AbstractText> |
5,924 | Catheter ablation of stable ventricular tachycardia before defibrillator implantation in patients with coronary heart disease (VTACH): a multicentre randomised controlled trial. | In patients with ventricular tachycardia (VT) and a history of myocardial infarction, intervention with an implantable cardioverter defibrillator (ICD) can prevent sudden cardiac death and thereby reduce total mortality. However, ICD shocks are painful and do not provide complete protection against sudden cardiac death. We assessed the potential benefit of catheter ablation before implantation of a cardioverter defibrillator.</AbstractText>The Ventricular Tachycardia Ablation in Coronary Heart Disease (VTACH) study was a prospective, open, randomised controlled trial, undertaken in 16 centres in four European countries. Patients aged 18-80 years were eligible for enrolment if they had stable VT, previous myocardial infarction, and reduced left-ventricular ejection fraction (LVEF; <or=50%). 110 patients were randomly allocated in a 1:1 ratio to receive catheter ablation and an ICD (ablation group, n=54) or ICD alone (control group, n=56). Randomisation was done by computer-generated randomly permuted blocks and stratified by centre and LVEF (<or=30% or >30%). Patients were followed up for at least 1 year. The primary endpoint was the time to first recurrence of VT or ventricular fibrillation (VF). Analysis was by intention to treat (ITT). This study is registered with ClinicalTrials.gov, number NCT00919373.</AbstractText>107 patients were included in the ITT population (ablation group, n=52; control group, n=55). Two patients (one in each group) withdrew consent immediately after randomisation without any follow-up data and one patient (ablation group) was excluded because of a protocol violaton. Mean follow-up was 22.5 months (SD 9.0). Time to recurrence of VT or VF was longer in the ablation group (median 18.6 months [lower quartile 2.4, upper quartile not determinable]) than in the control group (5.9 months [IQR 0.8-26.7]). At 2 years, estimates for survival free from VT or VF were 47% in the ablation group and 29% in the control group (hazard ratio 0.61; 95% CI 0.37-0.99; p=0.045). Complications related to the ablation procedure occurred in two patients; no deaths occurred within 30 days after ablation. 15 device-related complications requiring surgical intervention occurred in 13 patients (ablation group, four; control group, nine). Nine patients died during the study (ablation group, five; control group, four).</AbstractText>Prophylactic VT ablation before defibrillator implantation seemed to prolong time to recurrence of VT in patients with stable VT, previous myocardial infarction, and reduced LVEF. Prophylactic catheter ablation should therefore be considered before implantation of a cardioverter defibrillator in such patients.</AbstractText>St Jude Medical.</AbstractText>Copyright 2010 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
5,925 | Ventricular fibrillation initiated by an electrocution injury and terminated by an implantable cardioverter-defibrillator. | A 52-year-old man with an implantable cardioverter-defibrillator (ICD) was accidentally electrocuted when a flagpole he was erecting contacted an overhead electrical power line. The electrocution injury initiated ventricular fibrillation. The ICD sensed the arrhythmia and delivered therapy, converting his rhythm to sinus rhythm. The patient had no subsequent cardiac or neurological sequelae. |
5,926 | [Which therapy for which patient? In daily practice]. | Although the important progress in the curative treatment of atrial fibrillation, the indications of the regularisation of the first episode and of the preventive treatment remain difficult. Without real proofs on the interest of maintain in sinus rhythm, the indications depend on the age of the patient, the clinical tolerance and the objective impact on left ventricular ejection fraction. |
5,927 | [Rate control in patients with atrial fibrillation]. | The objectives of rate control in patients with atrial fibrillation is to reduce symptoms, improve quality of live and minimize the risk of heart failure development. Based upon results of large randomized studies, this strategy can be chosen as a first line therapy in some patients including those with heart failure. The target ventricular rate is <or=85 bpm at rest and <or=115 bpm during moderate exercise. Drugs slowing the atrioventricular conduction are usually used alone or in combination to achieve this goal. Failure to control ventricular rate using drugs may lead to AV nodal ablation and pacemaker implantation with a conventional or a biventricular system according to patient initial hemodynamic conditions. |
5,928 | [Silent atrial fibrillation]. | Asymptomatic atrial fibrillation (AF) is common, may adversely affect quality of life, and above all can be as serious as symptomatic AF. The prevalence of AF reported in epidemiological studies is significantly underestimated, as asymptomatic AF is often not known about. The efficacy of pharmacological or non-pharmacological treatment is often overestimated if the only aim considered is symptomatic recurrences. Like symptomatic AF, asymptomatic AF justifies anticoagulation, depending on the risk of embolism. Estimating the risk of embolism only from symptomatic episodes may result in unjustified discontinuation of antithrombotic treatment. Finally, frequent asymptomatic episodes may worsen atrial or even ventricular remodelling and result in tachycardia-induced cardiomyopathy. |
5,929 | Prediction of appropriate defibrillator therapy in heart failure patients treated with cardiac resynchronization therapy. | The necessity of implantable cardioverter-defibrillator (ICD) implantation in patients with systolic heart failure (HF) who undergo cardiac resynchronization therapy (CRT) may be questioned. The aim of this study was to identify patients at low risk for sustained ventricular arrhythmia. One hundred sixty-nine consecutive patients with HF (mean age 60 +/- 12 years, 125 men, 73% in New York Heart Association class III) referred for CRT and prophylactic, primary prevention ICD implantation underwent baseline clinical and echocardiographic assessment and regular device follow-up. The primary study end point was appropriate ICD therapy. During a mean follow-up period of 654 +/- 394 days, 35 patients (21%) had sustained ventricular arrhythmias requiring appropriate ICD therapy. Of the 3 patients who experienced sudden cardiac death, 2 had been treated with appropriate ICD therapy before sudden cardiac death. In a multivariate model, only history of nonsustained ventricular tachycardia (p = 0.001), a severely (<20%) decreased left ventricular ejection fraction (p = 0.001), and digitalis therapy (p = 0.08) independently predicted appropriate ICD therapy. Patients with 0 (n = 46), 1 (n = 36), 2 (n = 73), and 3 (n = 14) risk factors for appropriate ICD therapy had a 7%, 14%, 27%, and 64% and 0%, 6%, 10%, and 43% incidence of appropriate ICD therapy for ventricular arrhythmias and for rapid ventricular tachycardia or ventricular fibrillation, respectively. In conclusion, apart from commonsense considerations (age and significant co-morbidities), ICD addition seems ineffective in CRT patients without nonsustained ventricular tachycardia, digoxin therapy, and severely reduced left ventricular systolic function. |
5,930 | Intraoperative defibrillation threshold testing during implantable cardioverter-defibrillator insertion: do we really need it? | The assessment of defibrillation efficacy using a safety margin of 10 J has long been the standard of care for insertion of implantable cardioverter-defibrillator (ICD), but physicians are concerned about complications related to induction test. Therefore, the need for testing has been recently questioned. The aim of our study was to assess the impact of defibrillation threshold (DFT) testing of ICD on the efficacy of ICD therapy.</AbstractText>We analyzed data obtained from follow-up visits of 122 consecutive patients who underwent ICD implantation at our institute from April 1996 to June 2008, with (n = 42) or without (n = 80) DFT testing. Patients in the DFT group were less likely to be men (83.3% vs 96.3%, P < .031) than those in the non-DFT group. Conversely, the 2 groups were similar in age, left ventricular ejection fraction at baseline, functional class, and underlying cardiovascular disease. Results during a 12-month follow-up, 13 (31.0%) and 30 (37.5%) ventricular tachyarrhythmic episodes were recorded in the DFT and non-DFT groups, respectively (P = .472). Antitachycardia pacing (ATP) terminated most of episodes, reducing the need of defibrillation at 7.7% in the DFT group and 3.3% in the non-DFT group (P = .533). Similar percentages of inappropriate ATP interventions (7.1% vs 3.8%, P = .413) and shock deliveries (2.4% vs 5.0%, P = .659) were recorded between DFT and non-DFT groups.</AbstractText>At 1-year follow-up, the performance of DFT testing does not seem to add any significant efficacy advantage in patients undergoing ICD implantation. Prospective randomized trials and long-term follow-up are warranted to clarify whether routine DFT testing may be safely abandoned leading to a revision of current guidelines.</AbstractText>Copyright 2010 Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,931 | Hypertrophic cardiomyopathy in the elderly. | Hypertrophic cardiomyopathy (HCM) is a relatively common genetic cardiac disorder with heterogeneous morphological, functional and clinical features. Although the risk of sudden death and incapacitating symptoms in young patients has been focused upon, the disease has been found with increasing frequency in elderly patients. However, there have been few studies on clinical features of HCM in the elderly. We established a cardiomyopathy registration study in Kochi Prefecture, which is one of the most aged communities in Japan, to provide detailed descriptions of the clinical features of HCM in a community-based patient cohort. The unselected regional HCM population consisted largely of elderly patients (70% of the study cohort being >or=60 years of age at registration), although HCM has been regarded largely as a disease of the young. Cardiac hypertrophy that becomes clinically apparent late in life can be a genetic disorder, and mutations in the cardiac myosin-binding protein C gene are the most common cause of late-onset or elderly HCM. In the morphological features, sarcomere gene defects seem to have a predilection for a crescent-shaped left ventricular cavity with reversed septal curvature even in elderly patients, although an ovoid left ventricular shape was frequently seen in elderly patients in previous clinical studies on morphological characteristics of HCM. In middle-aged or elderly patients with HCM, heart failure and embolic events, which were strongly associated with atrial fibrillation, were very important. It is important to manage HCM patients from the standpoint of longitudinal evolution in order to prevent those clinical complications. |
5,932 | Cardiac arrest caused by undersensing of a temporary epicardial pacemaker. | The R-on-T phenomenon is a well-known entity that predisposes to dangerous arrhythmias. Typically, a premature ventricular complex occurring at the critical time during the T wave of the preceding beat precipitates ventricular tachycardia and fibrillation. This phenomenon can occur not only in asynchronous ventricular pacemakers, but also in synchronous pacemakers, if loss of sensing of the intrinsic rhythm becomes evident. A patient who was fitted with a temporary epicardial wire, following cardiac surgery and experienced repeated episodes of polymorphic ventricular tachycardia caused by the R-on-T phenomenon, is described.</Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Chemello</LastName><ForeName>D</ForeName><Initials>D</Initials><AffiliationInfo><Affiliation>Toronto General Hospital, University Health Network, Canada.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Subramanian</LastName><ForeName>A</ForeName><Initials>A</Initials></Author><Author ValidYN="Y"><LastName>Kumaraswamy</LastName><ForeName>N</ForeName><Initials>N</Initials></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D002363">Case Reports</PublicationType><PublicationType UI="D016428">Journal Article</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Can J Cardiol</MedlineTA><NlmUniqueID>8510280</NlmUniqueID><ISSNLinking>0828-282X</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D000368" MajorTopicYN="N">Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D001026" MajorTopicYN="N">Coronary Artery Bypass</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004562" MajorTopicYN="N">Electrocardiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004868" MajorTopicYN="N">Equipment Failure</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006323" MajorTopicYN="N">Heart Arrest</DescriptorName><QualifierName UI="Q000209" MajorTopicYN="Y">etiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D010138" MajorTopicYN="N">Pacemaker, Artificial</DescriptorName><QualifierName UI="Q000009" MajorTopicYN="Y">adverse effects</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017180" MajorTopicYN="N">Tachycardia, Ventricular</DescriptorName><QualifierName UI="Q000209" MajorTopicYN="Y">etiology</QualifierName><QualifierName UI="Q000503" MajorTopicYN="N">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D013686" MajorTopicYN="N">Telemetry</DescriptorName></MeshHeading></MeshHeadingList><OtherAbstract Type="Publisher" Language="fre">Le phénomène R/T est une entité bien connue qui prédispose à de dangereuses arythmies. D’ordinaire, un complexe ventriculaire prématuré se produisant au moment critique pendant l’onde T du battement précédent précipite une tachycardie et une fibrillation ventriculaires. Ce phénomène peut se produire non seulement avec des stimulateurs cardiaques ventriculaires asynchrones, mais également avec des stimulateurs cardiaques synchrones si la perte de détection du rythme intrinsèque devient évidente. On présente le cas d’un patient à qui on avait installé un fil épicardique temporaire après une chirurgie cardiaque et qui a présenté des épisodes répétés de tachycardie ventriculaire polymorphe causés par le phénomène R/T. |
5,933 | Long-term prognosis of patients diagnosed with Brugada syndrome: Results from the FINGER Brugada Syndrome Registry. | Brugada syndrome is characterized by ST-segment elevation in the right precordial leads and an increased risk of sudden cardiac death (SCD). Fundamental questions remain on the best strategy for assessing the real disease-associated arrhythmic risk, especially in asymptomatic patients. The aim of the present study was to evaluate the prognosis and risk factors of SCD in Brugada syndrome patients in the FINGER (France, Italy, Netherlands, Germany) Brugada syndrome registry.</AbstractText>Patients were recruited in 11 tertiary centers in 4 European countries. Inclusion criteria consisted of a type 1 ECG present either at baseline or after drug challenge, after exclusion of diseases that mimic Brugada syndrome. The registry included 1029 consecutive individuals (745 men; 72%) with a median age of 45 (35 to 55) years. Diagnosis was based on (1) aborted SCD (6%); (2) syncope, otherwise unexplained (30%); and (3) asymptomatic patients (64%). During a median follow-up of 31.9 (14 to 54.4) months, 51 cardiac events (5%) occurred (44 patients experienced appropriate implantable cardioverter-defibrillator shocks, and 7 died suddenly). The cardiac event rate per year was 7.7% in patients with aborted SCD, 1.9% in patients with syncope, and 0.5% in asymptomatic patients. Symptoms and spontaneous type 1 ECG were predictors of arrhythmic events, whereas gender, familial history of SCD, inducibility of ventricular tachyarrhythmias during electrophysiological study, and the presence of an SCN5A mutation were not predictive of arrhythmic events.</AbstractText>In the largest series of Brugada syndrome patients thus far, event rates in asymptomatic patients were low. Inducibility of ventricular tachyarrhythmia and family history of SCD were not predictors of cardiac events.</AbstractText> |
5,934 | Severe lactic acidosis after an iatrogenic propylene glycol overdose. | Propylene glycol is a diluent found in many intravenous and oral drugs, including phenytoin, diazepam, and lorazepam. Propylene glycol is eliminated from the body by oxidation through alcohol dehydrogenase to form lactic acid. Under normal conditions, the body converts lactate to pyruvate and metabolizes pyruvate through the Krebs cycle. Lactic acidosis has occurred in patients, often those with renal dysfunction, who were receiving prolonged infusions of drugs that contain propylene glycol as a diluent. We describe a 50-year-old man who experienced severe lactic acidosis after receiving an accidental overdose of lorazepam, which contains propylene glycol. The patient was acutely intoxicated, with a serum ethanol concentration of 406 mg/dl. He had choked on a large piece of meat and subsequently experienced pulseless electrical activity with ventricular fibrillation cardiac arrest. He was brought to the emergency department; within 2 hours, he was admitted to the intensive care unit for initiation of the hypothermia protocol. The patient began to experience generalized tonic-clonic seizures 12 hours later, which resolved after several boluses of lorazepam. A lorazepam infusion was started; however, it was inadvertently administered at a rate of 2 mg/minute instead of the standard rate of 2 mg/hour. Ten hours later, the administration error was recognized and the infusion stopped. The patient's peak propylene glycol level was 659 mg/dl, pH 6.9, serum bicarbonate level 5 mEq/L, and lactate level 18.6 mmol/L. Fomepizole was started the next day and was continued until hospital day 3. Continuous renal replacement therapy was started and then replaced with continuous venovenous hemofiltration (CVVH) for the remainder of the hospital stay. The patient's acidosis resolved by day 3, when his propylene glycol level had decreased to 45 mg/dl. Fomepizole was discontinued, but the patient's prognosis was poor (anoxic brain injury); thus care was withdrawn and the patient died. Although the patient's outcome was death, his lactic acidosis was treated successfully with fomepizole and CVVH. Clinicians should be aware that an iatrogenic overdose of lorazepam may result in severe propylene glycol toxicity, which may be treated with fomepizole and CVVH. |
5,935 | Mechanical mitral valve thrombosis and giant left atrial thrombus: comparison of transesophageal echocardiography and 64-slice multidetector computed tomography. | We report on the use of multidetector computed tomography (MDCT) in the diagnosis of prosthetic heart valve thrombosis and a giant left atrial (LA) thrombus extending into the LA appendage (LAA), in comparison with findings of transesophageal echocardiography (TEE). A 52-year-old woman with an eight-year history of mechanical mitral valve (MMV) replacement presented with progressive dyspnea. The electrocardiogram (ECG) showed atrial fibrillation. Transesophageal echocardiography showed severely increased MMV gradients and decreased MMV area. Two thrombi were identified on the atrial aspect of the MMV, one restricting the motion of the lateral leaflet, and the other localized on the septal side of the valve ring. Two other thrombi were also visualized, one in the LA and the other in the LAA, measuring 4.3 x 1.3 cm and 2.1 x 1 cm, respectively. ECG-gated 64-slice contrast-enhanced MDCT depicted a thrombus, involving both atrial and ventricular aspects of the MMV, and also a giant thrombus, 8.3 x 2.4 cm in size, in the LA extending into the LAA. The patient underwent redo-mitral valve replacement, LA thrombectomy, and LAA ligation, and was discharged uneventfully. The size and localization of thrombi in the LA and on the explant MMV matched to the findings of MDCT. In this case, MDCT was superior to TEE in showing the precise nature of both MMV thrombosis and the integrated thrombus involving the LA and LAA. |
5,936 | [Cardiac arrest due to accidental hypothermia and prolonged cardiopulmonary resuscitation]. | In cardiac arrest produced by accidental hypothermia, cardiopulmonary resuscitation must be prolonged until normal body temperature is achieved. There are different rewarming methods. In theory, the more invasive ones are elective in patients with cardiac arrest because of their higher rewarming speed. However, it has not been proven that these methods are better than the non-invasive ones. We present a case report of a patient with cardiac arrest due to accidental hypothermia who was treated without interruption for three hours with heart massage. This is the longest successful cardiopulmonary resuscitation known up-to-date in Spain. In order to rewarm the body, a combination of non-invasive methods was used: active external rewarming with convective warm air, gastric and bladder lavage with warm saline solution and intravenous warm saline infusion. This case shows that it is possible to treat hypothermic cardiac arrest successfully through these rewarming methods, which are both easy to apply and feasible in any hospital. |
5,937 | [Results of the first year of experience of the cardiopulmonary resuscitation program "Juan Ramón Jiménez" Hospital (Huelva)]. | To present the results of the first year of the functioning of a Cardiopulmonary Resuscitation (CPR) Hospital Plan and to describe the characteristics of the patients with cardiopulmonary arrest (CPA) in hospital units with no monitoring facilities (HU).</AbstractText>An observational, prospective study in a cohort of patients who presented CPA during a one-year period.</AbstractText>HU of a general hospital and as province reference.</AbstractText>Patients admitted to an HU from May 2007 to May 2008 with CPA and treated according to a specific hospital CPA Program, organized in order to: (a) decentralize the CPR through the training of the nurse as the first responder capable of performing immediate CPR and early defibrillation (DF) (less than 4 min), (b) a specific phone number as hospital alarm of CPR and (c) maintenance of the CPR maneuvers by an early intervention Resuscitation Team (RT) (less than 8 min).</AbstractText>Characteristics of patients, CPA episode and results according to the <<Utstein style>>.</AbstractText>A total of 73 patients were included with activation of the CPA alarm, 8 of which were false alarms, with an average age of 70 years and 60% men. A total of 65% occurred in the medical area in patients with heart or respiratory failure, sepsis or septic shock. Initial heart rhythm of the patients attended was asystolic in 74% of the patients, ventricular fibrillation in 18% and electromechanical dissociation in 8%. The first attending person was the nurse in 79% of cases, CPR was always initiated in less than 1 min, DF in less than 2 min (92%) and RT in less than 8 min (96%). Fifty-five percent survived and 35% of the reanimated patients were discharged live from the hospital, 78% with good neurological outcomes.</AbstractText>The CPR "Juan Ramón Jiménez" Hospital Program is an applicable and effective initiative in our setting.</AbstractText>Copyright 2009 Elsevier España, S.L. y SEMICYUC. All rights reserved.</CopyrightInformation> |
5,938 | A case of fatal caffeine poisoning. | Caffeine is a natural alkaloid methylxanthine that is found in various plants such as coffee or tea. Symptoms of a severe overdose may present with hypokalemia, hyponatremia, ventricular arrhythmias, hypertension followed by hypotension, respiratory failure, seizures, rhabdomyolysis, ventricular fibrillation and finally circulatory collapse. A 21-year-old woman called for the ambulance herself soon after the ingestion of about 10,000 mg of caffeine. At the arrival of the ambulance, the patient went into cardiac arrest almost immediately. After a total resuscitation period of 34 min including seven counter-shocks and 2 mg epinephrine, the patient was stable enough to be transferred to the hospital. The patient soon went into VF again and received two more counter-shocks and 1 mg epinephrine and finally an intravenous bolus dose of 300 mg amiodarone. The initial arterial blood gas showed pH at 6.47, lactate at 33 mmol/l and potassium level at 2.3 mmol/l. Unfortunately, no blood samples for caffeine analysis were taken. Three days after hospital admission, the patient developed myoclonus, which did not respond to medical treatment. Excessive intake of caffeine may produce arrhythmias and pronounced hypokalemia and ensuing ventricular fibrillation. In case of counter-shock-resistant VF, it can be necessary to give an early loading dose of amiodarone. Furthermore, it may be beneficial to replace the potassium as early as possible. Epinephrine and buffer solutions used during resuscitation may further decrease blood potassium levels and should be administrated cautiously. Epinephrine can be replaced by other vasopressor drugs, such as vasopressin without effects on beta-receptors. |
5,939 | [A simulation study of the effects of ischemia on spiral waves in 2D human ventricular tissue]. | Based on human ventricular single cell mathematical model, a two-dimensional mesh of ventricular wall tissue was constructed. Through the increasing of the concentration of extracellular K+, we simulated the propagation of spiral wave in a condition under the influence of ischemia in 2-D human ventricular tissue. The results showed that along with the increase of ischemic level and size, the instability of spiral waves increased, and under the influence of certain ischemic level and size, spiral waves broke up. Through this simulation study of the effects of ischemia on spiral waves in 2-D human ventricular tissue, we explained the corresponding mechanism of the maintenance of ventricular tachycardia and the cause of ventricular fibrillation under the influence of ischemia. |
5,940 | Self assessment exercises in Intensive Care Medicine. | Intensive Care Medicine (ICM) is no longer the exclusive preserve of anaesthetists as both emergency medicine and general medicine trainees now also train in this increasingly important speciality. This edition of the JRAMC self assessment question series serves to cover some of the current 'hot topics' in ICM and enables readers with experience of ICM to test their knowledge as well as educating junior trainees in relevant subjects that they may be unfamiliar with. Similarly, the Focus On .... series of papers elsewhere in this journal demonstrate the increasing importance of ICM in the deployed Field Hospital setting. |
5,941 | Transmural dispersion of repolarization in failing and nonfailing human ventricle. | Transmural dispersion of repolarization has been shown to play a role in the genesis of ventricular tachycardia and fibrillation in different animal models of heart failure (HF). Heterogeneous changes of repolarization within the midmyocardial population of ventricular cells have been considered an important contributor to the HF phenotype. However, there is limited electrophysiological data from the human heart.</AbstractText>To study electrophysiological remodeling of transmural repolarization in the failing and nonfailing human hearts.</AbstractText>We optically mapped the action potential duration (APD) in the coronary-perfused scar-free posterior-lateral left ventricular free wall wedge preparations from failing (n=5) and nonfailing (n=5) human hearts. During slow pacing (S1S1=2000 ms), in the nonfailing hearts we observed significant transmural APD gradient: subepicardial, midmyocardial, and subendocardial APD80 were 383+/-21, 455+/-20, and 494+/-22 ms, respectively. In 60% of nonfailing hearts (3 of 5), we found midmyocardial islands of cells that presented a distinctly long APD (537+/-40 ms) and a steep local APD gradient (27+/-7 ms/mm) compared with the neighboring myocardium. HF resulted in prolongation of APD80: 477+/-22 ms, 495+/-29 ms, and 506+/-35 ms for the subepi-, mid-, and subendocardium, respectively, while reducing transmural APD80 difference from 111+/-13 to 29+/-6 ms (P<0.005) and presence of any prominent local APD gradient. In HF, immunostaining revealed a significant reduction of connexin43 expression on the subepicardium.</AbstractText>We present for the first time direct experimental evidence of a transmural APD gradient in the human heart. HF results in the heterogeneous prolongation of APD, which significantly reduces the transmural and local APD gradients.</AbstractText> |
5,942 | Efficacy of continuous positive airway pressure on arrhythmias in obstructive sleep apnea patients. | The purpose of this study was to determine the relationship between obstructive sleep apnea (OSA) and cardiovascular disorders in a large Japanese population, and to assess the efficacy of continuous positive airway pressure (CPAP) in the treatment of OSA-associated arrhythmias. The study population comprised 1394 Japanese subjects (1086 men and 308 women) who were divided into four groups on the basis of polysomnography (PSG) analysis as follows: the no sleep apnea (N-SA) group (n = 44, apnea-hypopnea index [AHI] < 5), the mild OSA (Mi-OSA) group (n = 197, 5 < AHI < 15), the moderate OSA (Mo) group (n = 368, 15 < AHI < 30), and severe OSA (SOSA) group (n = 785, AHI < 30). The following baseline characteristics were significantly associated with OSA: age (P < 0.001), gender (P < 0.001), body mass index (P < 0.001), hypertension (P < 0.001), diabetes (P = 0.009), and hyperlipidemia (P = 0.013). In the OSA group, PSG revealed the predominance of paroxysmal atrial fibrillation (PAF) (P = 0.051), premature atrial complex short run (P < 0.005), premature ventricular complex (PVC, P = 0.004), sinus bradycardia (P = 0.036), and sinus pause (arrest >2 s, P < 0.001) during the PSG recording. A total of 316 patients from the group underwent CPAP titration and were then re-evaluated. Continuous positive airway pressure therapy significantly reduced the occurrences of PAF (P < 0.001), PVC (P = 0.016), sinus bradycardia (P = 0.001), and sinus pause (P = 0.004). The results of this study demonstrate a significant relationship between OSA and several cardiac disorders, and also demonstrate the efficacy of CPAP in preventing OSA-associated arrhythmias in a large population of Japanese patients. |
5,943 | Stenting and surgery for coronary vasospasm : the wrong solution fails to solve the problem. | A 55-year-old man, with a history of medically uncontrolled coronary vasospasm, presented for evaluation of chest pain 6 months after implantation of left internal mammary artery. Due to recurrent episodes of vasospastic angina and serious complications of coronary spasm (ventricular fibrillation, myocardial infarction), a stent had previously been implanted in the proximal part of left anterior descending artery at the site of angiographically and ergonovine-proven coronary spasm, with subsequent in-stent restenosis. |
5,944 | [Ventricular tachycardias originating in the his-purkinje system. Bundle branch reentrant ventricular tachycardias and fascicular ventricular tachycardias]. | Ventricular tachycardias (VT) associated with the His-Purkinje system may occur in patients with and without organic heart disease. The former may encounter bundle branch reentrant VT, a macroreentrant VT utilizing the specific conduction system. It frequently occurs in patients with preexisting conduction disturbance such as complete left bundle branch block and may be eliminated by catheter ablation of the right bundle branch. After successful ablation, patient's prognosis depends on the presence or absence of structural heart disease.In patients without structural heart disease, VT with right bundle branch block pattern and superior axis, referred to as idiopathic left ventricular tachycardia, is observed. It is a reentrant VT utilizing the posterior left fascicle and the Purkinje network. The two treatment options include antiarrhythmic drug therapy with verapamil or curative catheter ablation.Another form of ventricular arrhythmia originating in the Purkinje network is idiopathic ventricular fibrillation (IVF). Focal triggers from the right and left ventricular Purkinje network induce premature ventricular contractions inducing IVF. This is amenable to catheter ablation leading to a significant reduction in ICD (implantable cardioverter defibrillator) interventions in sudden cardiac death survivors. |
5,945 | [Limits and scopes of invasive risk stratification. Do we still need programmed ventricular stimulation?]. | Patients with ischemic heart disease and left ventricular systolic dysfunction (ICM), dilated (DCM), hypertrophic (HCM), or arrhythmogenic right ventricular cardiomyopathy (ARVCM) carry a high risk of sudden cardiac death (SCD). Ventricular tachyarrhythmias are most often the cause of SCD, which can be treated with internal cardioverter defibrillators (ICDs). However, a great proportion of these high-risk patients will never experience potentially lethal ventricular arrhythmias, and as such will never be in need of these devices. Given the risks, inconvenience, and costs of ICDs, markers that adequately stratify patients according to their risk of SCD are needed. Programmed ventricular stimulation (PVS) has long been used to identify the patients' risk of SCD. However, the prognostic ability of PVS is only modest and the negative predictive value is poor. As far as patients with ICM are concerned, recent data from the MUSTT and MADIT II trials demonstrate that in patients with a left ventricular ejection fraction between 30% and 40%, inducibility by PVS can help to identify patients who are at particularly increased risk of SCD. The value of PVS in patients with DCM, HCM, and ARVCM for risk stratification of SCD is less clear and the available data even more limited. In these patients, the inducibility of ventricular tachyarrhythmias does not clearly correlate with VT/VF (ventricular tachycardia/ventricular fibrillation) risk, and more importantly, noninducibility does not portend good prognosis. The current German guidelines appreciate these uncertainties of PVS for risk stratification with class IIb recommendations in certain patients with ICM, HCM or ARVCM. In the future, combining the results of invasive PVS with other noninvasive parameters may improve its prognostic value. Furthermore, expanding the role of PVS to guiding therapeutic ablation of ventricular arrhythmias may influence patient's future risk of SCD. |
5,946 | Correlates of NT-proBNP concentration in patients with essential hypertension in absence of congestive heart failure. | N-terminal proBNP (NT-proBNP) is widely used as a diagnostic biomarker and for the risk stratification of patients with heart failure (HF). Its role in the evaluation of patients with essential hypertension (EHT) is less clear. We examined the relationship between NT-proBNP concentrations and various clinical characteristics in hypertensive patients without HF.</AbstractText>This study included 186 consecutive patients with EHT and no history of HF, ischemic heart disease, or atrial fibrillation. Single and multiple variable regression analyses were performed in search of clinical correlates of NT-proBNP concentrations.</AbstractText>In patients with EHT, median serum concentration of NT-proBNP was 73 pg/ml, and interquartile range (IQR) was 40-128 pg/ml. NT-proBNP was significantly higher (P<0.001) in women (87 pg/ml; IQR 55-137 pg/ml) than in men (52 pg/ml; IQR 24-115 pg/ml). Age (r=0.371, P<0.001), precordial QRS voltage (r=0.223, P<0.001), hemoglobin (Hgb) concentration, (r=-0.208, P=0.023) and estimated glomerular filtration rate (r=-0.139, P=0.044) were correlated with log-transformed NT-proBNP by multiple variable analysis. In men, age (r=0.453, P<0.001) and QRS voltage (r=0.283, P=0.004), and in women age (r=0.299, P=0.006), QRS voltage (r=0.212, P=0.019), Hgb (r=-0.182, P=0.049), and estimated glomerular filtration rate (r=-0.272, P=0.009) were correlated with serum concentrations of NT-proBNP.</AbstractText>Age, gender, Hgb, left ventricular hypertrophy and renal function were correlated with NT-proBNP in patients with EHT.</AbstractText> |
5,947 | A Dutch case of a takotsubo cardiomyopathy after pacemaker implantation. | An 83-year-old female patient with symptomatic atrial fibrillation was referred to the Department of Cardiology for a scheduled electrocardioversion. Because of a junctional escape rhythm after the electrocardioversion she received a DDD pacemaker which was complicated by dyspnoea and ST-segment elevations in the inferior and precordial leads. Because of suspicion of an acute myocardial infarction she was transferred to a PCI centre. The coronary angiogram showed no abnormalities. In the initial phase, an echocardiogram was performed. The echocardiogram showed apical akinesis and a reduced left ventricular function. During follow-up left ventricular function improved and was completely normal nine weeks after the event. The clinical picture was interpreted as a takotsubo cardiomyopathy after a pacemaker implantation. (Neth Heart J 2009;17:487-90.). |
5,948 | A clinical comparison between a new dual-chamber pacing mode-AAIsafeR and DDD mode. | The aim of this study was to compare the cross-follow-up results in DDD or AAISafeR mode and to describe the safety and effectiveness of this pacing mode.</AbstractText>The Symphony 2450/2550 cardiac pacemakers were implanted in 30 patients with sick sinus syndrome between February 2006 and September 2006. They were randomized to the DDD mode or AAISafeR mode for 3 months and then crossed over to the alternate pacing modality for an additional 3 months.</AbstractText>No AAISafeR-related adverse event was observed. All documented episodes of paroxysmal atrial ventricular block caused the immediate switch of the pacing mode from AAI to DDD. The cumulative percent ventricular pacing was significantly reduced in the AAISafeR mode compared with the DDD mode (0.9% [0%-3%] versus 51.3% [2%-91%] P = 0.001; 2.94% [0%-18%] versus 41.18% [0%-65%] P = 0.0001). After 3 months in DDD mode, left atrial diameter, left ventricular enddiastolic diameter, and left ventricular end-systolic diameter increased significantly and left ventricular ejection fraction decreased. However, no obvious changes appeared in 3 months of AAISafeR mode. Switches to DDD occurred during follow-up in 21 patients due to different-degree atrial ventricular block.</AbstractText>The AAISafeR mode substantially reduces the amount of unnecessary right ventricular pacing in the bradycardia population and effectively prevents the deleterious effects on cardiac performance. An international randomized study will further ascertain the efficacy of this new pacing mode specifically in the prevention of heart failure hospitalization and atrial fibrillation.</AbstractText> |
5,949 | Intermediate-term effects of transcatheter secundum atrial septal defect closure on cardiac remodeling in children and adults. | The study aimed to investigate the intermediate-term effects of transcatheter atrial septal defect (ASD) closure on cardiac remodeling in children and adult patients. Between December 2003 and February 2009, 117 patients (48 males, 50 adults) underwent transcatheter ASD closure with the Amplatzer septal occluder (ASO). The mean age of the patients was 15 years, and the mean follow-up period was 25.9 +/- 12.4 months. New York Heart Association (NYHA) class, electrocardiographic parameters, and transthoracic echocardiographic (TTE) examination were evaluated before the ASD closure, then 1 day, 1 month, 6 months, 12 months, and yearly afterward. Transcatheter ASD closure was successfully performed for 112 (96%) of the 117 patients. The mean ASD diameter measured by transesophageal echocardiography (TEE) was 14.0 +/- 4.2 mm, and the mean diameter stretched with a sizing balloon was 16.6 +/- 4.8 mm. The mean size of the implanted device was 18.6 +/- 4.9 mm. The Qp/Qs ratio was 2.2 +/- 0.8. The mean systolic pulmonary artery pressure was 40 +/- 10 mmHg. At the end of the mean follow-up period of 2 years, the indexed right ventricular (RV) end-diastolic diameter had decreased from 36 +/- 5 to 30 +/- 5 mm/m(2) (p = 0.005), and the indexed left ventricular (LV) end-diastolic diameter had increased from 33 +/- 5 to 37 +/- 6 mm/m(2) (p = 0.001), resulting in an RV/LV ratio decreased from 1.1 +/- 0.2 to 0.8 +/- 0.2 (p = 0.001). The New York Heart Association (NYHA) functional capacity of the patients was improved significantly 24 months after ASD closure (1.9 +/- 0.5 to 1.3 +/- 0.5; p = 0.001). At the 2-year follow up electrocardiographic examination, the P maximum had decreased from 128 +/- 15 to 102 +/- 12 ms (p = 0.001), the P dispersion had decreased from 48 +/- 11 to 36 +/- 9 ms (p = 0.001), and the QT dispersion had decreased from 66 +/- 11 to 54 +/- 8 ms (p = 0.001). Five of six patients experienced resolution of their preclosure arrhythmias, whereas the remaining patient continued to have paroxysmal atrial fibrillation. A new arrhythmia (supraventricular tachycardia) developed in one patient and was well controlled medically. Transcatheter ASD closure leads to a significant improvement in clinical status and heart cavity dimensions in adults and children, as shown by intermediate-term follow-up evaluation. Transcatheter ASD closure can reverse electrical and mechanical changes in atrial myocardium, resulting in a subsequent reduction in P maximum and P dispersion times. |
5,950 | Abnormal restitution property of action potential duration and conduction delay in Brugada syndrome: both repolarization and depolarization abnormalities. | This study sought to examine the action potential duration restitution (APDR) property and conduction delay in Brugada syndrome (BrS) patients. A steeply sloped APDR curve and conduction delay are known to be important determinants for the occurrence of ventricular fibrillation (VF).</AbstractText>Endocardial monophasic action potential was obtained from 39 BrS patients and 9 control subjects using the contact electrode method. Maximum slopes of the APDR curve were obtained at both the right ventricular outflow tract (RVOT) and the right ventricular apex (RVA). The onset of activation delay (OAD) after premature stimulation was examined as a marker of conduction delay. Maximum slope of the APDR curve in BrS patients was significantly steeper than that in control subjects at both the RVOT and the RVA (0.77 +/- 0.21 vs. 058 +/- 0.14 at RVOT, P = 0.009; 0.98 +/- 0.23 vs. 0.62 +/- 0.16 at RVA, P = 0.001). The dispersion of maximum slope of the APDR curve between the RVOT and the RVA was also larger in BrS patients than in control subjects. The OAD was significantly longer in BrS patients than in control subjects from the RVOT to RVA and from the RVA to RVOT (from RVOT to RVA: 256 +/- 12 vs. 243 +/- 7 ms, P = 0.003; from RVA to RVOT: 252 +/- 11 vs. 241 +/- 9 ms, P = 0.01).</AbstractText>Abnormal APDR properties and conduction delay were observed in BrS patients. Both repolarization and depolarization abnormalities are thought to be related to the development of VF in BrS patients.</AbstractText> |
5,951 | Increase in pre-shock pause caused by drug administration before defibrillation: an observational, full-scale simulation study. | The importance of circulation during cardiopulmonary resuscitation has led to efforts to decrease time without chest compressions ("no-flow time"). The no-flow time from the interruption of chest compressions until defibrillation is referred to as the "pre-shock pause". A shorter pre-shock pause increases the chance of successful defibrillation. It is unclear whether drug administration affects the length of the pre-shock pause. Our study compares pre-shock pause with and without drug administration in a full-scale simulation.</AbstractText>This was an observational study in an ambulance including 72 junior physicians and a cardiac arrest scenario. Data were extracted by reviewing video recordings of the resuscitation. Sequences including defibrillation and/or drug administration were identified and assigned to one out of four categories: Defibrillation only (DC-only) and drug administration just prior to defibrillation (Drug+DC) for which the pre-shock pause was calculated, and drug administration alone (Drug-only) for which pre-drug time was calculated.</AbstractText>DC-only sequences were identified in 68/72 simulations, Drug+DC in 24/72, and Drug-only in 33/72. Median pre-shock pauses were 18s (DC-only) and 32 (Drug+DC), and median pre-drug pause 6. The variation between pauses was statistically significant (p<<0.001). DC-only and Drug+DC sequences was found in 22/72 simulations. A statistically significant difference of 8s was found between the median pre-shock pauses: 17s (DC-only) and 25 (Drug+DC) (p<<0.001). For un-paired observations, the pre-shock pause increased with 78% and for paired observations 47%.</AbstractText>Drug administration prior to defibrillation was associated with significant increases in pre-shock pauses in this full-scale simulation study.</AbstractText>Copyright 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,952 | Monitoring in resuscitation: comparison of cardiac output measurement between pulmonary artery catheter and NICO. | The cardiac output and coronary perfusion pressure generated from chest compressions during resuscitation manoeuvres can predict effectiveness and successful outcome. Until now, there is no good method for haemodynamic monitoring during resuscitation. Noninvasive partial carbon dioxide rebreathing system (NICO, Novametrix Medical Systems, Inc., Wallingford, CT, USA) is a relatively new non-invasive alternative to thermodilution for measuring cardiac output. The accuracy of the NICO system has not been evaluated during resuscitation. The aim of this study is to compare thermodilution cardiac output method with NICO system and to assess the utility of NICO during resuscitation.</AbstractText>Experimental study in 24 Yorkshire pigs. Paired measurements of cardiac output were determined during resuscitation (before ventricular fibrillation and after 5, 15, 30 and 45 min of resuscitation) in the supine position. The average of 3 consecutive thermodilution cardiac output measurements (10 ml 20 degrees C saline) was compared with the corresponding NICO measurement.</AbstractText>Bland and Altman plot and Lin's concordance coefficient showed a high correlation between NICO and thermodilution cardiac output measurements although NICO has a tendency to underestimate cardiac output when compared to thermodilution at normal values of cardiac output.</AbstractText>There is a high degree of agreement between cardiac output measurements obtained with NICO and thermodilution cardiac output during resuscitation. The present study suggests that the NICO system may be useful to measure cardiac output generated during cardiopulmonary resuscitation.</AbstractText>Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,953 | Deaths in custody: are some due to electronic control devices (including TASER devices) or excited delirium? | Deaths have occurred after law-enforcement incidents involving applications of electronic control devices (ECDs) (including TASER devices). An "excited delirium" syndrome (reported in the literature prior to the development of ECDs currently in use), however, includes several factors that may be related to such deaths in custody. In this review, potential detrimental effects of ECDs are compared with possible changes due to excited delirium. Although extreme (i.e., long-duration or repeated) exposures to ECDs can result in significant hyperkalaemia, acidaemia, and myoglobinemia in animal models, limited applications (such as those normally used in law-enforcement situations) would appear to have only transient effects. In addition, the hyperthermia observed in patients with excited delirium does not seem to be directly exacerbated by ECD applications. ECD use is unlikely to be a common cause of ventricular fibrillation, but other events that are generally associated with excited delirium (e.g., drug use) may be related to subsequent ventricular fibrillation or asystole. Metabolic or respiratory acidosis may only be serious consequences of long-duration or repeated ECD applications. On the basis of current available information, factors other than ECDs themselves may be more important when death occurs after the use of ECDs. |
5,954 | Diabetes is associated with impaired myocardial performance in patients without significant coronary artery disease. | Patients with diabetes mellitus (DM) have high risk of heart failure. Whether some of the risk is directly linked to metabolic derangements in the myocardium or whether the risk is primarily caused by coronary artery disease (CAD) and hypertension is incompletely understood. Echocardiographic tissue Doppler imaging was therefore performed in DM patients without significant CAD to examine whether DM per se influenced cardiac function.</AbstractText>Patients with a left ventricular (LV) ejection fraction (EF) > 35% and without significant CAD, prior myocardial infarction, cardiac pacemaker, atrial fibrillation, or significant valve disease were identified from a tertiary invasive center register. DM patients were matched with controls on age, gender and presence of hypertension.</AbstractText>In total 31 patients with diabetes and 31 controls were included. Mean age was 58 +/- 12 years, mean LVEF was 51 +/- 7%, and 48% were women. No significant differences were found in LVEF, left atrial end systolic volume, or left ventricular dimensions. The global longitudinal strain was significantly reduced in patients with DM (15.9 +/- 2.9 vs. 17.7 +/- 2.9, p = 0.03), as were peak longitudinal systolic (S') and early diastolic (E') velocities (5.7 +/- 1.1 vs. 6.4 +/- 1.1 cm/s, p = 0.02 and 6.1 +/- 1.7 vs. 7.7 +/- 2.0 cm/s, p = 0.002). In multivariable regression analyses, DM remained significantly associated with impairments of S' and E', respectively.</AbstractText>In patients without significant CAD, DM is associated with an impaired systolic longitudinal LV function and global diastolic dysfunction. These abnormalities are likely to be markers of adverse prognosis.</AbstractText> |
5,955 | Advanced age, low left atrial appendage velocity, and factor V promoter sequence variation as predictors of left atrial thrombosis in patients with nonvalvular atrial fibrillation. | Atrial fibrillation (AF) renders individual patients at risk for development of an atrial thrombus. The aim of this study was to determine clinical and echocardiographic factors influencing the risk of left atrial thrombosis (LAT) in patients with persistent nonvalvular AF. Genetic variants encoding haemostatic factors have been also assessed for putative association with LAT. In the cross-sectional study, a total of 212 patients (132 males and 80 females) with nonvalvular persistent AF (duration range 48 h-90 days) have been selected. LAT was visualized by transesophageal echocardiography. The FGB G(-455)A, PAI-1 4G/5G, F5 C(-224)T, and F5 R506Q genetic markers were tested using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) approach. To reveal independent factors contributing to the thromboembolic risk in AF, a multivariate logistic model was applied. LA thrombi were found in 44 out of 212 subjects (21%). LAT was more frequently observed in patients at age >75 years (P < 0.001) and those who had reduced left ventricular ejection fraction <40% (LVEF; P < 0.001) and decreased left atrial appendage velocity <20 cm/s (LAAV; P < 0.001). Logistic regression analysis showed that advanced age (OR = 1.64 per decade P < 0.001), LVEF < 40% (OR = 2.12, P < 0.001), LAAV (OR = 1.56, P = 0.007), and TT genotype of F5 C(-224)T (OR = 2.42, P = 0.041) are associated with higher risk of LAT. Age >75 years, LVEF < 40%, LAAV < 20 cm/s, and Factor V C(-224)T variant independently contribute to the thromboembolic risk in AF. |
5,956 | Novel pharmacological approaches for antiarrhythmic therapy. | Arrhythmias are caused by the perturbation of physiological impulse formation, impaired conduction, or disturbed electrical recovery. Currently available antiarrhythmic drugs-perhaps with exception of amiodarone-are not sufficiently effective and are burdened by cardiac and extracardiac side effects that may offset their therapeutic benefits. Detailed knowledge about electrical and structural remodelling may provide a better understanding of the mechanisms leading to generation and maintenance of arrhythmias especially in the setting of underlying heart disease and accompanying autonomic dysfunction. Thus, targets for new pharmacological interventions could include atrial-selective ion channels (e.g. atrial I(Na), I(Kur) and I(K,ACh)), pathology-selective ion channels (constitutively active I(K,ACh), TRP channels), ischemia-uncoupled gap junctions, proteins related to malfunctioning intracellular Ca(2+) homeostasis (e.g. "leaky" ryanodine receptors, overactive Na(+),Ca(2+) exchanger) or risk factors for arrhythmias ("upstream" therapies). In ventricular arrhythmias implantable cardioverter-defibrillator devices rather than antiarrhythmic drugs are the safest treatment option. The domain for new approaches to drug treatment is atrial fibrillation. |
5,957 | The usefulness of minimal ventricular pacing and preventive AF algorithms in the treatment of PAF: the 'MinVPace' study. | The beneficial effects of atrial pacing on the incidence, duration and symptomatology of paroxysmal atrial fibrillation (PAF) may be negated by increased ventricular pacing. This prospective randomised study evaluates the effect of pacing algorithms that minimise ventricular pacing (MinVP) with and without anti-AF algorithms, on AF burden (AFB) in patients with symptomatic PAF.</AbstractText>Patients implanted with pacemakers with MinVP capability with AFB 1-70% were enrolled. Three different DDDRP devices were assessed. Following a 1-month induction phase, patients were randomised to MinVP with and without preventive AF algorithms or dual chamber rate adaptive pacemaker (DDDR) (AV delay (AVD) 150 ms) for 2 months per study phase. The primary outcome measure was AFB.</AbstractText>One hundred and ten patients were enrolled; of these, 66 (mean age 74.3 + or - 7.9, 56% males) had an AFB of 1-70% during the induction phase and completed all study phases. There was no significant difference in AFB between the control phase DDDR, 13.8% (95% CI 8.7 to 18.8), and MinVP, 14.4% (95% CI 9.4 to 19.4), or MinVP with AF algorithms enabled, 14.7% (95% CI 9.7 to 19.7), (p = 0.65 and p = 0.49, respectively). Median ventricular pacing was significantly higher during the control phase, 86.0% (IQR 72.8, 97.3), than in MinVP 2.0% (IQR 0.0, 14.1) and MinVP + algorithms 3.0% (IQR 0.4, 15.6), p = < 0.001.</AbstractText>MinVP algorithms are effective in reducing ventricular pacing. However, there is no significant reduction in AFB with minimal ventricular pacing algorithms in the short term. No additional benefit or adverse outcome was found with preventative anti-AF algorithms in combination with MinVP algorithms.</AbstractText> |
5,958 | A case report of central extracorporeal membrane oxygenation after implantation of a left ventricular assist system: femoral vein and left atrium cannulation for ECMO. | The left ventricular assist system (LVAS) is often used for end-stage heart failure. However, in severe lung disorder, the patient needs extracorporeal membrane oxygenation (ECMO) because oxygenation using only a ventricular assist system (VAS) is insufficient. We report a successful case of combining the use of LVAS and right VAS (RVAS) with ECMO.</AbstractText>A 40-year-old female developed cardiogenic shock secondary to end-stage dilated cardiomyopathy, and percutaneous cardiopulmonary support (PCPS) was initiated. An echocardiogram showed a low ejection fraction (11%), and she underwent implantation of an LVAS (Toyobo Ventricular Assist System). She also required a RVAS with ECMO shunting between the right and left atrium because there was insufficient oxygenation resulting from pulmonary dysfunction followed by severe lung edema.</AbstractText>Pulmonary function recovered successfully, and the RVAS-ECMO was removed after 7 days of support. There were no complications after operation, such as infection, bleeding, or systemic embolization.</AbstractText>LVAS combined with RVAS-ECMO in right and left atrial cannulation is a useful option for patients with severe pulmonary damage.</AbstractText> |
5,959 | Survival and neurological outcomes after nasopharyngeal cooling or peripheral vein cold saline infusion initiated during cardiopulmonary resuscitation in a porcine model of prolonged cardiac arrest. | We have previously demonstrated that nasopharyngeal cooling initiated during cardiopulmonary resuscitation improves the success of resuscitation. In this study, we compared the effects of nasopharyngeal cooling with cold saline infusion initiated during cardiopulmonary resuscitation on resuscitation outcome in a porcine model of prolonged cardiac arrest. We hypothesized that nasopharyngeal cooling initiated during cardiopulmonary resuscitation would yield better resuscitation outcome when compared with cold saline infusion.</AbstractText>Randomized, prospective animal study.</AbstractText>University-affiliated research laboratory.</AbstractText>Yorkshire-X domestic pigs (Sus scrofa).</AbstractText>Ventricular fibrillation was induced in 14 pigs weighing 38 +/- 2 kg. After 15 mins of untreated ventricular fibrillation, cardiopulmonary resuscitation was performed for 5 mins before defibrillation. Coincident with the start of cardiopulmonary resuscitation, animals were randomly assigned to receive nasopharyngeal cooling with the aid of the RhinoChill Device (BeneChill, San Diego, CA) or cold saline infusion with 30 mL/kg 4 degrees C saline. One hour after restoration of spontaneous circulation, surface cooling was begun with the aid of a water blanket in both groups and maintained for 4 hrs.</AbstractText>Jugular vein temperature significantly decreased in animals subjected to nasopharyngeal cooling in comparison with those receiving cold saline infusion (p < .01). Core temperature, however, decreased only in animals receiving cold saline infusion (p < .01). Coronary perfusion pressure was significantly higher in the animals treated with nasopharyngeal cooling (p = .02). All seven animals treated with nasopharyngeal cooling were successfully resuscitated in contrast to only two animals resuscitated in the cold saline infusion group (p = .02).</AbstractText>In this model, nasopharyngeal cooling initiated during cardiopulmonary resuscitation improved the success of resuscitation compared to cooling with cold saline infusion.</AbstractText> |
5,960 | Leaning during chest compressions impairs cardiac output and left ventricular myocardial blood flow in piglet cardiac arrest. | Complete recoil of the chest wall between chest compressions during cardiopulmonary resuscitation is recommended, because incomplete chest wall recoil from leaning may decrease venous return and thereby decrease blood flow. We evaluated the hemodynamic effect of 10% or 20% lean during piglet cardiopulmonary resuscitation.</AbstractText>Prospective, sequential, controlled experimental animal investigation.</AbstractText>University research laboratory.</AbstractText>Domestic piglets.</AbstractText>After induction of ventricular fibrillation, cardiopulmonary resuscitation was provided to ten piglets (10.7 +/- 1.2 kg) for 18 mins as six 3-min epochs with no lean, 10% lean, or 20% lean to maintain aortic systolic pressure of 80-90 mm Hg. Because the mean force to attain 80-90 mm Hg was 18 kg in preliminary studies, the equivalent of 10% and 20% lean was provided by use of 1.8- and 3.6-kg weights on the chest.</AbstractText>Using a linear mixed-effect regression model to control for changes in cardiopulmonary resuscitation hemodynamics over time, mean right atrial diastolic pressure was 9 +/- 0.6 mm Hg with no lean, 10 +/- 0.3 mm Hg with 10% lean (p < .01), and 13 +/- 0.3 mm Hg with 20% lean (p < .01), resulting in decreased coronary perfusion pressure with leaning. Microsphere-determined cardiac index and left ventricular myocardial blood flow were lower with 10% and 20% leaning throughout the 18 mins of cardiopulmonary resuscitation. Mean cardiac index decreased from 1.9 +/- 0.2 L . M . min with no leaning to 1.6 +/- 0.1 L . M . min with 10% leaning, and 1.4 +/- 0.2 L . M . min with 20% leaning (p < .05). The myocardial blood flow decreased from 39 +/- 7 mL . min . 100 g with no lean to 30 +/- 6 mL . min . 100 g with 10% leaning and 26 +/- 6 mL . min . 100 g with 20% leaning (p < .05).</AbstractText>Leaning of 10% to 20% (i.e., 1.8-3.6 kg) during cardiopulmonary resuscitation substantially decreased coronary perfusion pressure, cardiac index, and myocardial blood flow.</AbstractText> |
5,961 | Correlation between myocardial fibrosis and the occurrence of atrial fibrillation in hypertrophic cardiomyopathy: a cardiac magnetic resonance imaging study. | Cardiac magnetic resonance imaging (CMR) in hypertrophic cardiomyopathy (HCM) often shows delayed contrast enhancement (DE) representing regions of focal myocardial fibrosis. Atrial fibrillation (AF) is a commonly reported complication of HCM. We determined the relationship between the presence of left ventricular myocardial fibrosis (LVMF) detected by DE-CMR and the occurrence AF in a series of patients with HCM. 67 patients with HCM (47 males; mean age 50.1+/-18.5 years) were studied by CMR measuring mass of LVMF, left ventricular mass, volume and function, and left atrial (LA) area. AF was present in 17 (25%) patients. LVMF was observed in 57% of patients. AF was significantly more frequent in patients who also showed LVMF, compared with the group without LVMF (42.1% vs. 3.4%, respectively; p<0.0001). LA size was larger in patients showing DE (LA area: 37.4+/-11.1 vs. 25.9+/-6.8 cm(2); respectively, p=0.0001). AF in HCM is related with myocardial fibrosis detected by DE-CMR and dilatation of the LA. This fact adds to the proven adverse prognostic value of myocardial fibrosis in HCM, thus, reinforcing the usefulness of this technique in the assessment of these patients. |
5,962 | Ablation vs medical therapy in the setting of symptomatic atrial fibrillation and left ventricular dysfunction. | Small, single-center studies suggest that catheter ablation of atrial fibrillation (AF) can improve ventricular function and reduce symptoms in patients with left ventricular (LV) dysfunction. However, ablation has not been compared with a pharmacologic strategy for AF. The authors evaluated patients with AF and symptomatic LV dysfunction (ejection fraction < or =45%) referred for pulmonary vein isolation (PVI). They compared these patients with a matched cohort treated medically for AF and LV dysfunction via a retrospective case-control method. Fifteen patients (14 men, 56+/-11 years, 10 [67%] paroxysmal AF) with AF for 4+/-3 years underwent PVI. Baseline ejection fraction was 37%+/-6% and New York Heart Association (NYHA) class was 2.0+/-1.0. Fifteen controls (13 men, 63+/-14 years, 11 [73%] paroxysmal AF) with AF for 5+/-4 years were treated medically for AF. Baseline ejection fraction was 34%+/-11% and NYHA class was 2.0+/-0.7. The groups were similar in all respects. During a follow-up of 16+/-13 months after complete PVI, ejection fraction improved (P=.001) to 50%+/-13% and normalized in 8 patients (53%). NYHA class improved to 1.3+/-0.5 (P=.01). In the medically treated group, after follow-up of 16+/-12 months, no improvement in ejection fraction (36%+/-12%) or NYHA class (1.8+/-0.7) was seen. Compared with pharmacologic therapy, PVI significantly improved LV function and NYHA class in patients with AF and symptomatic LV dysfunction. These provocative findings provide potent rationale for a randomized clinical trial comparing ablation with pharmacologic therapy. |
5,963 | The atrial fibrillation paradox of heart failure. | The prevalence of atrial fibrillation (AF) in patients with heart failure (HF) is high, but longitudinal studies suggest that the incidence of AF is relatively low. The authors investigated this paradox prospectively in an epidemiologically representative population of patients with HF and persistent AF. In all, 891 consecutive patients with HF [mean age, 70+/-10 years; 70% male; left ventricular ejection fraction, 32%+/-9%] were enrolled. The prevalence of persistent AF at baseline was 22%. The incidence of persistent AF at 1 year was 26 per 1000 person-years, ranging from 15 in New York Heart Association class I/II to 44 in class III/IV. AF occurred either at the same time or prior to HF in 76% of patients and following HF in 24%. A risk score was developed to predict the occurrence of persistent AF. The annual risk of persistent AF developing was 0.5% (0%-1.3%) for those in the low-risk group compared with 15% (3.4%-26.6%) in the high-risk group. Despite a high prevalence of persistent AF in patients with HF, the incidence of persistent AF is relatively low. This is predominantly due to AF coinciding with or preceding the development of HF. The annual risk of persistent AF developing can be estimated from clinical variables. |
5,964 | The usefulness of microvolt T-wave alternans in the risk stratification of patients with hypertrophic cardiomyopathy. | Patients with hypertrophic cardiomyopathy are prone to ventricular arrhythmias and sudden death. Identifying patients at risk of sudden death is difficult.</AbstractText>To determine whether microvolt T-wave alternans detected during exercise or rapid atrial pacing can identify patients with HCM who are at risk of ventricular arrhythmias and sudden death.</AbstractText>This prospective observational study included 21 patients with HCM: the disease was abstructive in 11, nonobstructive in 9 and apical in 1. TWA was measured while the patients were on anti-arrhythmic medication.</AbstractText>TWA was positive in 9 patients (43%) and negative in 12 (57%). Three patients were resuscitated after sudden death before their enrollment in the study and two patients developed ventricular tachycardia and fibrillation respectively during the study period. After combining the endpoint of sudden death from a ventricular arrhythmia and the presence of ventricular arrhythmias on a Holter monitor, there was no significant correlation between the presence of a positive TWA and the presence of ventricular arrhythmias on the Holter monitor or a history of sudden death.</AbstractText>TWA cannot be used as a non-invasive test for detecting patients with HCM and electrical instability. TWA is not useful for predicting sudden death in patients with HCM.</AbstractText> |
5,965 | Intrapericardial ranolazine prolongs atrial refractory period and markedly reduces atrial fibrillation inducibility in the intact porcine heart. | Extensive experimental studies and clinical evidence (Metabolic Efficiency with Ranzolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome Thrombolysis in Myocardial Infarction-36 [MERLIN TIMI-36] trial) indicate potential antiarrhythmic efficacy of the antianginal agent ranolazine. Delivery of agents into the pericardial space allows high local concentrations to be maintained in close proximity to myocardial tissue while systemic effects are minimized.</AbstractText>The effects of intrapericardial (IPC) administration of ranolazine (50-mg bolus) on right atrial and right ventricular effective refractory periods (ERP), atrial fibrillation threshold, and ventricular fibrillation threshold were determined in 17 closed-chest anesthetized pigs. IPC ranolazine increased atrial ERP in a time-dependent manner from 129 +/- 5.14 to 186 +/- 9.78 ms (P < 0.01, N = 7) but did not significantly affect ventricular ERP (from 188.3 +/- 4.6 to 201 +/- 4.3 ms (NS, N = 6). IPC ranolazine increased atrial fibrillation threshold from 4.8 +/- 0.8 to 28 +/- 2.3 mA (P < 0.03, N = 6) and ventricular fibrillation threshold (from 24 +/- 3.56 baseline to 29.33 +/- 2.04 mA at 10-20 minutes, P < 0.03, N = 6). No significant change in mean arterial pressure was observed (from 92.8 +/- 7.1 to 74.8 +/- 7.5 mm Hg, P < 0.125, N = 5, at 7 minutes).</AbstractText>IPC ranolazine exhibits striking atrial antiarrhythmic actions as evidenced by increases in refractoriness and in fibrillation inducibility without significantly altering mean arterial blood pressure. Ranolazine's effects on the atria appear to be more potent than those on the ventricles.</AbstractText> |
5,966 | Distribution of pre-course BLS/AED manuals does not influence skill acquisition and retention in lay rescuers: a randomised study. | The present study aims to investigate whether the distribution of the Basic Life Support and Automated External Defibrillation (BLS/AED) manual, 4 weeks prior to the course, has an effect on skill acquisition, theoretical knowledge and skill retention, compared with courses where manuals were not distributed.</AbstractText>A total of 303 laypeople were included in the present study. The courses were randomised with sealed envelopes in 12 courses, where manuals were distributed to participants (group A) and in 12 courses, where manuals were not distributed to participants (group B). The participants were formally evaluated at the end of the course, and at 1, 3 and 6 months after each course. The evaluation procedure was the same at all time intervals and consisted of two distinct parts: a written test and a simulated cardiac arrest scenario.</AbstractText>No significant difference was observed between the two groups in skill acquisition at the time of initial training. Furthermore, there was no significant difference between the groups in performing BLS/AED skills at 1, 3 and 6 months after initial training. Theoretical knowledge in either group at the specified time intervals did not exhibit any significant difference. Significant deterioration of skills was observed in both groups between initial training and at 1 month after the course, as well as between the first and third month after the course.</AbstractText>The present study shows that distribution of BLS/AED manuals 1 month prior to the course has no effect on theoretical knowledge, skill acquisition and skill retention in laypeople.</AbstractText>Copyright 2009 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,967 | Prevention of atrial fibrillation in cardiac surgery: time to consider a multimodality pharmacological approach. | Atrial fibrillation (AF) is very common within the first 5 days of cardiac surgery. It is associated with significant morbidity including stroke, ventricular arrhythmias, myocardial infarction, heart failure, acute kidney injury, prolonged hospital stay, and also short- and long-term mortality. The underlying mechanisms of developing AF after cardiac surgery are multifactorial; risk factors may include advanced age, withdrawal of beta-blockers and angiotensin-converting-enzyme inhibitors, valve surgery, obesity, increased left atrial size, and diastolic dysfunction. There are many pharmacological options in preventing AF, but none of them are effective for all patients and they all have significant limitations. Beta-blockers may reduce the incidence of AF by more than a third, but bradycardia, hypotension, or exacerbation of heart failure often limit their utility postoperatively. Recent evidence suggests that class III antiarrhythmic drugs, sotalol and amiodarone, are more effective than beta-blockers, but they both share similar hemodynamic side effects of beta-blockers. Magnesium, antiinflammatory drugs such as statins, omega fatty acids, and low-dose corticosteroids also have some efficacy and they have the advantages of not causing significant hemodynamic side effects. Data on effectiveness of calcium channel blockers, digoxin, alpha-2 agonists, sodium nitroprusside, and N-acetylcysteine are more limited. Because the pathogenesis of AF is multifactorial, a combination of drugs with different pharmacological actions may have additive or synergistic effect in preventing AF after cardiac surgery. Randomized controlled trials evaluating the effectiveness of a multimodality pharmacological approach in patients at high-risk of AF after cardiac surgery are needed. |
5,968 | Palliative atrial switch operation in a 22-year-old patient with transposition of the great arteries. | A 2-year-old boy was diagnosed as having transposition of the great arteries (TGA) and ventricular septal defect (VSD) and underwent pulmonary artery banding. The patient showed slow progression of cyanosis and dyspnea on exertion. Oxygen saturation was 70-75 % and cardiac catheterization showed severe pulmonary hypertension. At the age of 22, the patient underwent a palliative atrial switch operation; oxygen saturation increased to around 95 % and the patient experienced relief of symptoms. Atrial fibrillation and right side pleural effusion occurred but resolved and the patient was discharged. |
5,969 | Detrended fluctuation analysis predicts successful defibrillation for out-of-hospital ventricular fibrillation cardiac arrest. | Repeated failed shocks for ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OOHCA) can worsen the outcome. It is very important to rapidly distinguish between early and late VF. We hypothesised that VF waveform analysis based on detrended fluctuation analysis (DFA) can help predict successful defibrillation.</AbstractText>Electrocardiogram (ECG) recordings of VF signals from automated external defibrillators (AEDs) were obtained for subjects with OOHCA in Taipei city. To examine the time effect on DFA, we also analysed VF signals in subjects who experienced sudden cardiac death during Holter study from PhysioNet, a publicly accessible database. Waveform parameters including root-mean-squared (RMS) amplitude, mean amplitude, amplitude spectrum analysis (AMSA), frequency analysis as well as fractal measurements including scaling exponent (SE) and DFA were calculated. A defibrillation was regarded as successful when VF was converted to an organised rhythm within 5s after each defibrillation.</AbstractText>A total of 155 OOHCA subjects (37 successful and 118 unsuccessful defibrillations) with VF were included for analysis. Among the VF waveform parameters, only AMSA (7.61+/-3.30 vs. 6.30+/-3.13, P=0.028) and DFAalpha2 (0.38+/-0.24 vs. 0.49+/-0.24, P=0.013) showed significant difference between subjects with successful and unsuccessful defibrillation. The area under the curves (AUCs) for AMSA and DFAalpha2 was 0.63 (95% confidence interval (CI)=0.52-0.73) and 0.65 (95% CI=0.54-0.75), respectively. Among the waveform parameters, only DFAalpha2, SE and dominant frequency showed significant time effect.</AbstractText>The VF waveform analysis based on DFA could help predict first-shock defibrillation success in patients with OOHCA. The clinical utility of the approach deserves further investigation.</AbstractText>Copyright 2009 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,970 | Electrical storm in patients with implantable cardioverter-defibrillators: can it be forecast? | The aim of this retrospective study was to determine the prevalence and predictors of electrical storm in 227 patients who had received implantable cardioverter-defibrillators (ICDs) and had been monitored for 31.7 +/- 15.6 months. Of these, 174 (77%) were men. The mean age was 55.8 +/- 15.5 years (range, 20-85 yr), and the mean left ventricular ejection fraction (LVEF) was 0.30 +/- 0.14. One hundred forty-six of the patients (64%) had underlying coronary artery disease. Cardioverter-defibrillators were implanted for secondary (80%) and primary (20%) prevention. Of the 227 patients, 117 (52%) experienced events that required ICD therapy. Thirty patients (mean age, 57.26 +/- 14.3 yr) had > or = 3 episodes requiring ICD therapy in a 24-hour period and were considered to have electrical storm. The mean number of events was 12.75 +/- 15 per patient. Arrhythmia-clustering occurred an average of 6.1 +/- 6.7 months after ICD implantation. Clinical variables with the most significant association with electrical storm were low LVEF (P = 0.04; hazard ratio of 0.261, and 95% confidence interval of 0.08-0.86) and higher use of class IA antiarrhythmic drugs (P = 0.018, hazard ratio of 3.84, and 95% confidence interval of 1.47-10.05). Amiodarone treatment and use of beta-blockers were not significant predictors when subjected to multivariate analysis. We conclude that electrical storm is most likely to occur in patients with lower LVEF and that the use of Class IA antiarrhythmic drugs is a risk factor. |
5,971 | [Role of ACE-inhibitors in preventing atrial fibrillation relapses in normotensive patients]. | Atrial fibrillation (AF) is the most common chronic cardiac arrhythmia and a major public health problem, leading to high rates of morbidity and mortality. The most prevalent cause of AF in the western world is hypertensive heart disease. Blood pressure increase leads to hemodynamic modifications which usually have direct effects on left ventricular and atrial structure and function. The renin-angiotensin-aldosterone system (RAAS) plays an important role in regulating blood volume and systemic vascular resistance. Furthermore, recent studies showed that RAAS plays a key role in left atrial and ventricle structural and functional remodeling. Experimental studies and clinical trials have shown that angiotensin-II converting enzyme (ACE) inhibitors and angiotensin-II receptor blockers are effective in preventing atrial fibrillation in patients with arterial hypertension or several forms of heart disease. In our study, we showed that ramipril is effective in preventing AF relapses in patients with lone AF (LAF: i.e AF in the absence of clinical and echocardiographic evidence of cardiovascular, pulmonary, or endocrine disease), independently of any sizeable effect on cardiac echocardiographic anatomy when compared with baseline data. In this paper, we briefly discuss: 1) the role of ACE inhibitor ramipril in preventing AF relapses in LAF patients; 2) the underlying mechanisms by which it can potentially act; 3) the possibility of considering the occurrence of LAF as a marker of subclinical organ damage in subjects with blood pressure values in the 130 to 139 mm Hg range, that is in the pre-hypertension classification according to the JNC-7 Report, of high normal blood pressure levels according to the 2007 ESC/ESH guidelines. |
5,972 | 2-year survival of patients undergoing mild hypothermia treatment after ventricular fibrillation cardiac arrest is significantly improved compared to historical controls. | Therapeutic hypothermia has been proven to be effective in improving neurological outcome in patients after cardiac arrest due to ventricular fibrillation (VF). Data concerning the effect of hypothermia treatment on long-term survival however is limited.</AbstractText>Clinical and outcome data of 107 consecutive patients undergoing therapeutic hypothermia after cardiac arrest due to VF were compared with 98 historical controls. Neurological outcome was assessed at ICU discharge according to the Pittsburgh cerebral performance category (CPC). A Kaplan-Meier analysis of follow-up data concerning mortality after 24 months as well as a Cox-regression to adjust for confounders were calculated.</AbstractText>Neurological outcome significantly improved after mild hypothermia treatment (hypothermia group CPC 1-2 59.8%, control group CPC 1-2 24.5%; p < 0.01). In Kaplan-Meier survival analysis hypothermia treatment was also associated with significantly improved 2-year probability for survival (hypothermia 55% vs. control 34%; p = 0.029). Cox-regression analysis revealed hypothermia treatment (p = 0.031) and age (p = 0.013) as independent predictors of 24-month survival.</AbstractText>Our study demonstrates that the early survival benefit seen with therapeutic hypothermia persists after two years. This strongly supports adherence to current recommendations regarding postresuscitation care for all patients after cardiac arrest due to VF and maybe other rhythms as well.</AbstractText> |
5,973 | Estimating the probability that the Taser directly causes human ventricular fibrillation. | This paper describes the first methodology and results for estimating the order of probability for Tasers directly causing human ventricular fibrillation (VF). The probability of an X26 Taser causing human VF was estimated using: (1) current density near the human heart estimated by using 3D finite-element (FE) models; (2) prior data of the maximum dart-to-heart distances that caused VF in pigs; (3) minimum skin-to-heart distances measured in erect humans by echocardiography; and (4) dart landing distribution estimated from police reports. The estimated mean probability of human VF was 0.001 for data from a pig having a chest wall resected to the ribs and 0.000006 for data from a pig with no resection when inserting a blunt probe. The VF probability for a given dart location decreased with the dart-to-heart horizontal distance (radius) on the skin surface. |
5,974 | Therapeutic hypothermia with immunosuppressive drugs for a comatose renal transplant patient who survived out-of-hospital cardiac arrest. | A 31-year-old man suddenly collapsed at work. His colleagues witnessed the event, applied basic life support, and called for an ambulance. After the ambulance arrived, the initial rhythm was confirmed as ventricular fibrillation (VF) and he was defibrillated with an automated external defibrillator. Spontaneous circulation was regained at 8 min after collapse. He was thought to be a good candidate for therapeutic hypothermia because he was comatose and had survived outside hospital VF cardiac arrest due to cardiac etiology. However, he was taking immunosuppressive drugs after undergoing a kidney transplant. We obtained written, informed consent from the patient's family to start therapeutic hypothermia at 33.5-34.5 °C for 48 h, although he was at high risk for such induction. Serious complications and neurological deficits did not develop and the patient was referred to another hospital on day 42 for implantation with a cardioverter defibrillator. |
5,975 | Unusual presentation of thyrotoxicosis as complete heart block and renal failure: a case report. | Thyrotoxicosis is a clinical entity often very difficult to diagnose without biochemical confirmation as its clinical features can be highly varied. The most common cardiac manifestations of thyrotoxicosis are resting sinus tachycardia, supraventricular tachycardia including atrial fibrillation and atrial flutter with or without cardiac failure. Bradycardia and atrio-ventricular conduction defects are very uncommon in thyrotoxicosis.</AbstractText>We report the case of a 59-year-old Caucasian man presenting with progressive weight loss, abnormal liver function, acute renal failure and complete heart block due to thyrotoxicosis.</AbstractText>Thyrotoxicosis should be considered as a possible diagnosis in patients with bradycardia and heart blocks associated with abnormal symptoms like weight loss. Nevertheless, the clinical, electrophysiological and biochemical abnormalities associated with thyrotoxicosis may be completely reversible restoring euthyroid state.</AbstractText> |
5,976 | Repair of ventricle free wall rupture after acute myocardial infarction: a case report. | Acute myocardial infarction (AMI) may culminate in sudden death by ventricular fibrillation, cardiogenic shock, and cardiac rupture. We present a case of postinfarction rupture treated by direct closure and coronary artery bypass grafting after thrombolytic therapy.</AbstractText>A 67-year-old woman with cardiac risk factors of hypertension, diabetes mellitus, and being post-menopausal was admitted complaining of chest pain and sweating. Thrombolytic therapy with streptokinase was started due to acute myocardial infarction. But, reperfusion criteria were not achieved. Echocardiography revealed a moderate pericardial effusion with mild right chamber collapse and pericardial thrombus. Cardiac catheterization revealed totally occluded left anterior descending (LAD) and circumflex coronary arteries. She was taken to the operating-room immediately. The pericardium was opened and a large amount of blood with thrombus was removed. Her hemodynamic indices improved immediately. There was active bleeding from multiple sites with a 4 mm rupture. Cardiopulmonary bypass was established. Direct closure of rupture was carried out. Reversed autogenous saphenous vein bypass grafts were placed to the LAD and second obtuse margin coronary arteries. Postoperative recovery was uneventful and she was discharged from hospital in good condition. She remained asymptomatic during first year following the surgery.</AbstractText>This case demonstrates that left ventricular free wall rupture is not always fatal and that early diagnosis and emergency surgical therapy may be successful. The combination of surgical repair with revascularization should be considered, because 80% of patients who experience LVFWR have multivessel coronary artery disease.</AbstractText> |
5,977 | Genetic variation in SCN10A influences cardiac conduction. | To identify genetic factors influencing cardiac conduction, we carried out a genome-wide association study of electrocardiographic time intervals in 6,543 Indian Asians. We identified association of a nonsynonymous SNP, rs6795970, in SCN10A (P = 2.8 x 10(-15)) with PR interval, a marker of cardiac atrioventricular conduction. Replication testing among 6,243 Indian Asians and 5,370 Europeans confirmed that rs6795970 (G>A) is associated with prolonged cardiac conduction (longer P-wave duration, PR interval and QRS duration, P = 10(-5) to 10(-20)). SCN10A encodes Na(V)1.8, a sodium channel. We show that SCN10A is expressed in mouse and human heart tissue and that PR interval is shorter in Scn10a(-/-) mice than in wild-type mice. We also find that rs6795970 is associated with a higher risk of heart block (P < 0.05) and a lower risk of ventricular fibrillation (P = 0.01). Our findings provide new insight into the pathogenesis of cardiac conduction, heart block and ventricular fibrillation. |
5,978 | Purkinje activation precedes myocardial activation following defibrillation after long-duration ventricular fibrillation. | While reentry within the ventricular myocardium (VM) is responsible for the maintenance of short-duration ventricular fibrillation (SDVF; VF duration <1 minute), Purkinje fibers (PFs) are important in the maintenance of long-duration ventricular fibrillation (LDVF; VF duration >1 minute).</AbstractText>The purpose of this study was to test the hypothesis that the mechanisms of defibrillation may also be different for SDVF and LDVF.</AbstractText>A multielectrode basket catheter was deployed in the left ventricle of eight beagles. External defibrillation shocks were delivered with a ramp-up protocol after SDVF (20 seconds) and LDVF (150 seconds). Earliest VM and PF activations were identified after the highest energy shock that failed to terminate VF and the successful shock.</AbstractText>Defibrillation was successful after 36 +/- 12 and 181 +/- 14 seconds for SDVF and LDVF, respectively. The time after shock delivery until earliest activation was detected for failed shocks and was significantly longer after LDVF (138.7 +/- 24.1 ms) than after SDVF (75.6 +/- 8.7 ms). Earliest postshock activation after SDVF typically initiated in the VM (14 of 16 episodes), while it always initiated in the PF (16 of 16 episodes) after LDVF. Sites of earliest activity during sinus rhythm correlated with sites of earliest postshock activation for PF-led cycles but not for VM-led cycles.</AbstractText>Earliest recorded postshock activation is in the Purkinje system after LDVF but not after SDVF. This difference raises the possibility that the optimal defibrillation strategy is different for SDVF and LDVF.</AbstractText>Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,979 | Left ventricular ejection fraction and absence of ACE inhibitor/angiotensin II receptor blocker predicts appropriate defibrillator therapy in the primary prevention population. | Implantable cardioverter defibrillators (ICD) significantly reduce mortality in patients with left ventricular (LV) dysfunction. However, little is known of the predictors of appropriate device activation in the primary prevention population. The aim of the present study was to determine predictors of appropriate device therapy in patients receiving ICDs for primary prevention.</AbstractText><AbstractText Label="METHODS & RESULTS" NlmCategory="RESULTS">One hundred twenty-six patients with a left ventricular ejection fraction (LVEF) of < 35% and no prior documented ventricular arrhythmias underwent ICD implantation. The ICD implanted was single chamber in 60 (48%), dual chamber in 10 (8%), and biventricular in 56 (44%) patients and programmed with a single ventricular fibrillation (VF) zone at >180 beats per minute. Mean age was 58 +/- 13 years and mean LVEF was 23 +/- 7%. Fifty-two percent had ischemic cardiomyopathy and 66% were New York Heart Association heart failure class II/III. During a mean follow-up period of 589 +/- 353 days, 17 (13%) patients received appropriate device therapy and three (4%) received inappropriate shocks. Appropriate ICD therapy was associated with reduced LVEF (mean 19.9% vs 23.7%, P = 0.02) and the patients were less likely to have received angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blockers (AIIRB) (65% vs 90%, P = 0.04). Multivariate analysis revealed lack of ACEI/AIIRB (odds ratio [OR]= 0.06, 95% confidence interval [CI]= 0.01-0.37, P = <0.01) and lower LVEF (OR = 0.88, 95% CI 0.79-0.98, P = 0.02) predicted appropriate device activation. There was no difference in transplant-free survival between the appropriate therapy and no/inappropriate therapy groups, LVEF <20% and LVEF >20% group, and lack of ACEI/AIIRB and ACEI/AIIRB group.</AbstractText>Appropriate device activation occurred in 13% of patients in a primary prevention population. LVEF and absence of ACEI/AIIRB predicted appropriate ICD therapy.</AbstractText> |
5,980 | High efficacy of disopyramide in the management of ventricular fibrillation storms in a patient with Brugada syndrome. | The patient was a 57-year-old man with Brugada syndrome, who had been implanted with a implantable cardioverter defibrillator (ICD). The frequency of ventricular fibrillation (VF) started to increase about 4 years after ICD implantation, occurring, at worst, six times in one night. Immediately after starting oral administration of disopyramide, VF stopped occurring. He then discontinued taking disopyramide, but immediately after the discontinuation VF started occurring again, so he restarted taking disopyramide. Thereafter, VF completely stopped occurring. Findings observed in our case suggest that disopyramide could be added in our arsenal of medications for treating arrhythmic storms in patient with Brugada syndrome. |
5,981 | A decrease in serum aldosterone level is associated with maintenance of sinus rhythm after successful cardioversion of atrial fibrillation. | The activation of the renin-angiotensin-aldosterone system has been implicated in the progression of atrial structural remodeling during atrial fibrillation (AF). However, consequences of the changes of aldosterone in AF have not been evaluated.</AbstractText>This study's aim was to evaluate changes of serum aldosterone concentration after successful cardioversion of persistent AF and to determine the prognostic value of these changes.</AbstractText>The prospective, single center study included 45 consecutive patients with nonvalvular persistent AF and preserved left ventricular systolic function, referred for cardioversion. None of the patients were taking aldosterone antagonists. Blood samples for aldosterone measurement were collected twice: 24 hours before and 24 hours after cardioversion.</AbstractText>Forty-three patients were successfully converted to sinus rhythm. On the 30th day following cardioversion, 24 patients maintained sinus rhythm (group A), 19 patients relapsed to AF (group B). Serum aldosterone concentration before cardioversion did not differ significantly between both groups (175.6 +/- 112.82 pg/mL vs 125.8 +/- 51.2 pg/mL; P = 0.25). However, in group A serum aldosterone level decreased significantly within 24 hours after cardioversion, from 175.6 +/- 112.8 pg/mL to 101.4 +/- 44.2 pg/mL (P = 0.0034). In group B, the aldosterone level before and after cardioversion did not differ significantly (125.8 +/- 51.2 pg/mL vs 118.2 +/- 59.6 pg/mL; P = 0.68). Logistic regression analysis revealed that a decrease in plasma aldosterone concentration after direct current cardioversion more than 13.2 pg/mL predicted sinus rhythm maintenance in a 30-day follow-up, with 87% sensitivity and 64% specificity.</AbstractText>There is a positive correlation between the fall in aldosterone concentration 24 hours after cardioversion and maintenance of sinus rhythm during 30 days of observation.</AbstractText> |
5,982 | Twiddling with an implantable cardioverter-defibrillator. | A 64-year-old woman underwent implantation of a single-chamber implantable cardioverter-defibrillator. The active fixation lead was positioned in the right ventricular apex and the generator in a left pre-pectoral pocket. Device interrogation 4weeks after implantation revealed inappropriate sensing and failure of pacing. A chest X-ray showed the entire lead coiled behind the device. The patient admitted manipulating the device and a diagnosis of Twiddler's syndrome was made. After repositioning the lead, the generator was re-located in the sub-pectoral position to help prevent recurrence by reducing the ability to externally manipulate the device. |
5,983 | Novel use of a subcutaneous shock lead to create an epicardial implantable cardioverter/defibrillator system via a limited thoracotomy. | We report the case of a novel use of a subcutaneous shock lead to create an epicardial implantable cardioverter/defibrillator (ICD) system via a limited thoracotomy in a patient with poor vascular access. Performance of the system is comparable to the conventional ICD system without the disadvantages of other available epicardial ICD systems. |
5,984 | Does time delay between the primary cardiac arrest and PCI affect outcome? | In patients with acute ST-segment elevation acute myocardial infarction (AMI), no data are available on the prognostic value of cardiac arrest (CA) due to ventricular fibrillation (VF) before, during, and after percutaneous coronary intervention (PCI). The aim of our study was to determine differences in prognosis between patients with CA before, during, and after PCI.</AbstractText>Among 448 patients with first ST-segment elevation AMI, we selected 34 (7.6%) with primary CA due to VF and 6 (1.3%) with secondary CA. The patients with primary CA were categorized into groups according to the time of the first episode of the primary CA, either before [12 (35.3%)], during [18 (52.9%)], or after [4 (11.8%)] PCI procedure. The 30-day all-cause mortality rate was analysed.</AbstractText>Short-term mortality was: (i) in patients without CA: 7.1% (29/408); (ii) in patients with primary CA 35.3% (12/34); (iii) in patients with secondary CA 50% (3/6); (P < 0.001). Mortality was 8.3% (1/12) in patients with primary CA before PCI; 44.4% (8/18) in patients with primary CA during PCI; 75% (3/4) in patients with primary CA after PCI procedure; (P = 0.007).</AbstractText>Patients with a primary CA have the same poor prognosis as patients with a secondary CA. The prognosis worsened according to the time of the occurrence of the primary CA. It might be reasonable to isolate subgroups of ST-segment elevation AMI patients treated with PCI with primary CA according to time of primary CA. This could help to better stratify the risk of these patients.</AbstractText> |
5,985 | CaMKII-dependent diastolic SR Ca2+ leak and elevated diastolic Ca2+ levels in right atrial myocardium of patients with atrial fibrillation. | Although research suggests that diastolic Ca(2+) levels might be increased in atrial fibrillation (AF), this hypothesis has never been tested. Diastolic Ca(2+) leak from the sarcoplasmic reticulum (SR) might increase diastolic Ca(2+) levels and play a role in triggering or maintaining AF by transient inward currents through Na(+)/Ca(2+) exchange. In ventricular myocardium, ryanodine receptor type 2 (RyR2) phosphorylation by Ca(2+)/calmodulin-dependent protein kinase (CaMK)II is emerging as an important mechanism for SR Ca(2+) leak.</AbstractText>We tested the hypothesis that CaMKII-dependent diastolic SR Ca(2+) leak and elevated diastolic Ca(2+) levels occurs in atrial myocardium of patients with AF.</AbstractText>We used isolated human right atrial myocytes from patients with AF versus sinus rhythm and found CaMKII expression to be increased by 40+/-14% (P<0.05), as well as CaMKII phosphorylation by 33+/-12% (P<0.05). This was accompanied by a significantly increased RyR2 phosphorylation at the CaMKII site (Ser2814) by 110+/-53%. Furthermore, cytosolic Ca(2+) levels were elevated during diastole (229+/-20 versus 164+/-8 nmol/L, P<0.05). Most likely, this resulted from an increased SR Ca(2+) leak in AF (P<0.05), which was not attributable to higher SR Ca(2+) load. Tetracaine experiments confirmed that SR Ca(2+) leak through RyR2 leads to the elevated diastolic Ca(2+) level. CaMKII inhibition normalized SR Ca(2+) leak and cytosolic Ca(2+) levels without changes in L-type Ca(2+) current.</AbstractText>Increased CaMKII-dependent phosphorylation of RyR2 leads to increased SR Ca(2+) leak in human AF, causing elevated cytosolic Ca(2+) levels, thereby providing a potential arrhythmogenic substrate that could trigger or maintain AF.</AbstractText> |
5,986 | Ventricular safety pacing, ventricular sense response, and ventricular tachycardia. | The ventricular sense response (VSR) algorithm enforces biventricular pacing on ventricular sensing to maximize biventricular pacing in patients with atrial fibrillation. This report describes a case of recurrent ventricular tachycardia that may be facilitated by this enforced pacing algorithm. |
5,987 | [Case of myocardial infarction during emergency clipping surgery of a cerebral aneurysm]. | An 80-year-old woman with subarachnoid hemorrhage underwent emergency neck clipping of a cerebral aneurysm. She had previously undergone surgery for an abdominal aortic aneurysm 10 years before. Anesthesia was induced with propofol and maintained with a combination of fentanyl and sevoflurane (0.5-1.5%) in air and oxygen. Ventricular fibrillation occurred immediately before clipping of the aneurysm, in the absence of preexisting myocardial ischemia, and recurred 4 times thereafter during the surgery. The ventricular fibrillation was successfully treated with cardioversion. We administered catecholamines, nitrates, calcium antagonists, nicorandil and heparin, following which the patient's hemodynamics gradually improved. After the operation, the patient was transferred to the cardiovascular center of a neighboring university where she successfully underwent emergency percutaneous transluminal coronary angioplasty. The patient was discharged from hospital 10 days later without any complications. Patients undergoing vascular surgical procedures or having a preoperative history of prior vascular surgery are at high risk for perioperative myocardial infarction. It is necessary to perform cardiac examination, including coronary angiography, preoperatively in such patients, even in those who are otherwise asymptomatic. |
5,988 | Ventricular fibrillation associated with use of synephrine containing dietary supplement. | As the prevalence of obesity increases in the United States, military personnel are turning to unregulated dietary supplements to aid in weight loss. Some of these supplements may cause more harm than benefit. We report the case of a 27-year-old active duty female who experienced an episode of ventricular fibrillation associated with the use of a dietary supplement containing synephrine. Recommendations for both physicians and the military regarding monitoring the use of these substances by active duty personnel are then provided. |
5,989 | Reduction of CPR artifacts in the ventricular fibrillation ECG by coherent line removal. | Interruption of cardiopulmonary resuscitation (CPR) impairs the perfusion of the fibrillating heart, worsening the chance for successful defibrillation. Therefore ECG-analysis during ongoing chest compression could provide a considerable progress in comparison with standard analysis techniques working only during "hands-off" intervals.</AbstractText>For the reduction of CPR-related artifacts in ventricular fibrillation ECG we use a localized version of the coherent line removal algorithm developed by Sintes and Schutz. This method can be used for removal of periodic signals with sufficiently coupled harmonics, and can be adapted to specific situations by optimal choice of its parameters (e.g., the number of harmonics considered for analysis and reconstruction). Our testing was done with 14 different human ventricular fibrillation (VF) ECGs, whose fibrillation band lies in a frequency range of [1 Hz, 5 Hz]. The VF-ECGs were mixed with 12 different ECG-CPR-artifacts recorded in an animal experiment during asystole. The length of each of the ECG-data was chosen to be 20 sec, and testing was done for all 168 = 14 x 12 pairs of data. VF-to-CPR ratio was chosen as -20 dB, -15 dB, -10 dB, -5 dB, 0 dB, 5 dB and 10 dB. Here -20 dB corresponds to the highest level of CPR-artifacts.</AbstractText>For non-optimized coherent line removal based on signals with a VF-to-CPR ratio of -20 dB, -15 dB, -10 dB, -5 dB and 0 dB, the signal-to-noise gains (SNR-gains) were 9.3 +/- 2.4 dB, 9.4 +/- 2.4 dB, 9.5 +/- 2.5 dB, 9.3 +/- 2.5 dB and 8.0 +/- 2.7 (mean +/- std, n = 168), respectively. Characteristically, an original VF-to-CPR ratio of -10 dB, corresponds to a variance ratio var(VF):var(CPR) = 1:10. An improvement by 9.5 dB results in a restored VF-to-CPR ratio of -0.5 dB, corresponding to a variance ratio var(VF):var(CPR) = 1:1.1, the variance of the CPR in the signal being reduced by a factor of 8.9.</AbstractText>The localized coherent line removal algorithm uses the information of a single ECG channel. In contrast to multi-channel algorithms, no additional information such as thorax impedance, blood pressure, or pressure exerted on the sternum during CPR is required. Predictors of defibrillation success such as mean and median frequency of VF-ECGs containing CPR-artifacts are prone to being governed by the harmonics of the artifacts. Reduction of CPR-artifacts is therefore necessary for determining reliable values for estimators of defibrillation success.</AbstractText>The localized coherent line removal algorithm reduces CPR-artifacts in VF-ECG, but does not eliminate them. Our SNR-improvements are in the same range as offered by multichannel methods of Rheinberger et al., Husoy et al. and Aase et al. The latter two authors dealt with different ventricular rhythms (VF and VT), whereas here we dealt with VF, only. Additional developments are necessary before the algorithm can be tested in real CPR situations.</AbstractText> |
5,990 | QRS complex abnormalities in subjects with idiopathic ventricular fibrillation. | Recent data point to a high incidence of early repolarization abnormalities among patients with idiopathic ventricular fibrillation (IVF). ECG data from 11 patients with idiopathic IVF were evaluated for the presence of initial (slurring or notching of the ascending limb of the R-wave that resembles a "pseudo" delta-wave) and terminal (slurring or notching of the descending limb of the R-wave resembling the early repolarization pattern) QRS complex abnormalities in at least two contiguous leads. The control group comprised 101 age- and gender-matched healthy individuals without structural heart disease in whom the presence of an accessory pathway was excluded during electrophysiological study. Initial QRS complex abnormalities in the setting of a normal PR interval were more frequent in subjects with IVF than in control population (36.4% vs. 8.9%, p=0.023). Although not statistically significant, an early repolarization pattern was also more common among patients with IVF (27.3% vs. 12.9%, p=0.192). Among patients with IVF, there is an increased prevalence of initial and terminal QRS complex abnormalities. |
5,991 | Honoring Leslie A. Geddes - farewell .. | Honor thy father and thy mother, say the Holy Scriptures1, for they at least gave thee this biological life, but honor thy teachers, too, for they gave thee knowledge and example.Leslie Alexander Geddes took off on a long, long trip, Sunday October 25, 2009, leaving his body for medical and research use. The departing station was West Lafayette, Indiana, where he set foot in 1974, at Purdue University, stamping there a unique deep imprint, similar and probably more profound than the one left at Baylor College of Medicine (BCM), Houston, Texas, in the period 1955-1974. Memories came back as a flood the minute after a message broke the news to me: When I first met him visiting the Department of Physiology at BCM back in 1962, my first Classical Physiology with Modern Instrumentation Summer Course ... The versatile Physiograph was the main equipment, an electronic-mechanical three or four channel recorder that could pick up a variety of physiological variables. Les and his collaborators had introduced also the impedance pneumograph, which was a simplified version of previous developments made by others. It became a ubiquitous unit that trod many roads in the hands of eager and curious students. Ventricular fibrillation and especially its counterpart, defibrillation, stand out as subjects occupying his concern along the years. Many were the students recruited to such effort and long is the list of papers on the subject. Physiological signals attracted considerable part of his activities because one of his perennial mottos was measurement is essential in physiology. He has written thirteen books and over eight hundred scientific papers, receiving also several prizes and distinctions. Not only his interests stayed within the academic environment but an industrial hue was manifested in over 20 USA patents, all applied to medical use. History of science and technology was another area in which, often with Hebbel Hoff, he uncovered astounding and delightful information. It is beyond my capability to review everything Les did, least of all what he did during the long span at Purdue. |
5,992 | Conduction delay in right ventricle as a marker for identifying high-risk patients with Brugada syndrome. | To evaluate the significance of conduction delay (CD) in the right ventricle (RV) in Brugada syndrome (BS) as a marker for risk stratification of sudden death.</AbstractText>Twenty-five patients with BS (7 with documented ventricular fibrillation (VF), 8 with syncope, and 10 without symptoms) and 10 control subjects were paced from the RV apex using 8 beats of drive pacing and a single extra-stimulus. CDs in the right ventricular outflow tract (RVOT) (CD-RV) and in the lateral left ventricle (L-LV) (CD-LV), and the local electrogram durations at a single extra-stimulus in RVOT (D-RV) and L-LV (D-LV) were calculated. We also evaluated changes in 12-lead ECG parameters in 16 patients with BS after pilsicainide challenge test (Pilsicainide-test).</AbstractText>Maximal CD-RV and maximal D-RV were significantly larger than maximal CD-LV and maximal D-LV in BS (26 +/- 10 and 105 +/- 15 vs 20 +/- 6 and 92 +/- 15 ms, P < 0.05, respectively). Maximal CD-RV and maximal D-RV in patients with documented VF were the largest among the 3 groups. There was a significant positive correlation between maximal CD-RV or maximal D-RV and changes in QRS duration in leads V2 and V5 and in S wave duration in lead II and V5 after Pilsicainide-test (CD-RV; r = 0.54, 0.51, 0.56, and 0.53: D-RV; r = 0.55, 0.5, 0.57, and 0.53, P < 0.05, respectively). In control subjects, there were no significant differences.</AbstractText>CD in RV was a useful marker for identifying high-risk patients with BS. CD in the RV, especially in the RVOT epicardium, may be related to arrhythmias in BS.</AbstractText> |
5,993 | Assessment of reperfusion following thrombolysis with mean fibrillation and amplitude spectrum area in patients with sustained ventricular fibrillation. | Improved microcirculatory reperfusion in patients with ventricular fibrillation (VF) enhances the electrical activity of the fibrillation process and increases the likelihood of successful defibrillation.</AbstractText>Changes in amplitude spectrum area (AMSA) and mean fibrillation (MF) in patients with sustained VF were analysed after administration of rt-PA variant tenecteplase in out-of-hospital cardiac arrest (OHCA) during cardiopulmonary resuscitation (CPR).</AbstractText>A total of 69 ECG sequences from nine patients were evaluated. Patients who received tenecteplase showed significantly longer duration of VF (p = 0.016). While AMSA declined significantly during CPR (p = 0.001), MF did not differ between groups. There were two survivors in the treatment group and one in the control group.</AbstractText>When tenecteplase was administered during CPR, VF lasted significantly longer than in controls. Changes in MF and AMSA did not indicate improved myocardial perfusion in patients who received tenecteplase during CPR.</AbstractText> |
5,994 | Caveat anicula! Beware of quiet little old ladies: demographic features, pharmacotherapy, readmissions and survival in a 10-year cohort of patients with heart failure and preserved systolic function. | To determine whether heart failure with preserved systolic function (HFPSF) has different natural history from left ventricular systolic dysfunction (LVSD).</AbstractText>A retrospective analysis of 10 years of data (for patients admitted between 1 July 1994 and 30 June 2004, and with a study census date of 30 June 2005) routinely collected as part of clinical practice in a large tertiary referral hospital.</AbstractText>Sociodemographic characteristics, diagnostic features, comorbid conditions, pharmacotherapies, readmission rates and survival.</AbstractText>Of the 2961 patients admitted with chronic heart failure, 753 had echocardiograms available for this analysis. Of these, 189 (25%) had normal left ventricular size and systolic function. In comparison to patients with LVSD, those with HFPSF were more often female (62.4% v 38.5%; P = 0.001), had less social support, and were more likely to live in nursing homes (17.9% v 7.6%; P < 0.001), and had a greater prevalence of renal impairment (86.7% v 6.2%; P = 0.004), anaemia (34.3% v 6.3%; P = 0.013) and atrial fibrillation (51.3% v 47.1%; P = 0.008), but significantly less ischaemic heart disease (53.4% v 81.2%; P = 0.001). Patients with HFPSF were less likely to be prescribed an angiotensin-converting enzyme inhibitor (61.9% v 72.5%; P = 0.008); carvedilol was used more frequently in LVSD (1.5% v 8.8%; P < 0.001). Readmission rates were higher in the HFPSF group (median, 2 v 1.5 admissions; P = 0.032), particularly for malignancy (4.2% v 1.8%; P < 0.001) and anaemia (3.9% v 2.3%; P < 0.001). Both groups had the same poor survival rate (P = 0.912).</AbstractText>Patients with HFPSF were predominantly older women with less social support and higher readmission rates for associated comorbid illnesses. We therefore propose that reduced survival in HFPSF may relate more to comorbid conditions than suboptimal cardiac management.</AbstractText> |
5,995 | Performance of chest compressions by laypersons during the Public Access Defibrillation Trial. | Increasing evidence indicates that health professionals often may not achieve guideline standards for cardiopulmonary resuscitation (CPR). Little is known about layperson CPR performance.</AbstractText>The investigation was a retrospective cohort study of cardiac arrest patients treated by layperson CPR and one model of automated external defibrillator (AED) as part of the Public Access Defibrillation Trial (n=26). CPR was measured using software that integrates the event log, ECG signal, and thoracic impedance signal. We assessed chest compression fraction (proportion of attempted resuscitation spent performing chest compressions), prompted compression fraction (proportion of attempted resuscitation spent performing compressions during AED-prompted periods), compression rate, and compressions per minute.</AbstractText>Of the 26 cases, 13 presented with ventricular fibrillation and 13 with nonshockable rhythms. Overall, during the period when patients did not have spontaneous circulation, the median chest compression fraction was 34% (IQR 17-48%), median prompted chest compression fraction was 49% (IQR 30-66%), and the median chest compression rate was 96/min (IQR 90-110/min). Taken together, the median chest compression delivered per minute among all arrests was 29 (IQR 20-42). CPR characteristics differed according to initial rhythm: median chest compression per minute was 20 (IQR 13-29) among ventricular fibrillation and 42 (IQR 28-47) among nonshockable rhythms (p=0.003).</AbstractText>In this study of trained laypersons, CPR varied substantially and often did not achieve guideline parameters. The findings suggest a need to improve CPR training, consider changes to CPR protocols, and/or improve the AED-rescuer interface.</AbstractText>Copyright 2009. Published by Elsevier Ireland Ltd.</CopyrightInformation> |
5,996 | Treatment of patients with supraventricular tachyarrhythmias in a medical intensive care unit. | Direct-current cardioversion has a higher success rate than does medical therapy in converting supraventricular tachyarrhythmias to sinus rhythm and should be performed immediately in patients with hemodynamic instability. Hemodynamically stable patients with atrial fibrillation or atrial flutter, a rapid ventricular rate and without preexcitation syndrome should be treated with intravenous beta-adrenergic blocking drugs, amiodarone, verapamil, or diltiazem. In hemodynamically unstable patients with supraventricular tachycardia, intravenous adenosine is the drug of choice. |
5,997 | Does syncope require rhythmic and non-rhythmic evaluation in patients with previous MI? | Multiple factors, in addition to left ventricular ejection fraction (LVEF) influence the risk of mortality in coronary artery disease. The purpose of this study was to evaluate the main causes of syncope after myocardial infarction (MI) and to propose an algorithm of management.</AbstractText>356 patients consecutively admitted for syncope and history of MI (>1 month), without ventricular tachycardia (VT), underwent echocardiography, Holter monitoring, head-up tilt test, exercise testing, signal-averaged ECG, electrophysiological study (EPS) and evaluation of coronary status. The mean follow-up was 4±2 years.</AbstractText>Monomorphic VT, ventricular flutter or fibrillation (VF) and supraventricular tachyarrhythmia were respectively induced at EPS in 87, 63 and 39 patients; conduction disturbances were noted in 23 patients, and 57 patients had several abnormalities. Among the 144 patients with negative EPS, coronary ischaemia was identified in 37 patients, and hypervagotonia in 27 patients. All studies remain negative in 84 patients (23.6%), more frequently women (p<0.001). Four patients died suddenly during follow-up. A longer QRS duration, a lower LVEF and grade IVa,b of Lown on Holter ECG were associated with the induction of VT. LVEF<40% and VT/VF induction were predictors of cardiac mortality, VT was a predictor of sudden death, and low LVEF and advanced age were predictors of death by heart failure.</AbstractText>Myocardial ischaemia, hypervagotonia, conduction abnormalities, ventricular or supraventricular tachyarrhythmias were identified in 76% of patients with syncope after MI. Several factors of syncope were found in 57 patients (16%). Non-invasive rhythmological and systematic coronary status assessment should be recommended in patients with syncope following MI.</AbstractText> |
5,998 | Dronedarone in the management of atrial fibrillation. | Atrial fibrillation is the most common type of tachyarrhythmia caused by multiple re-entrant wave forms within the atria and bombarding the atrioventricular node several times making it beat in a rapid, disorganized fashion termed "fibrillation". In atrial fibrillation, atria beat more than 300 times per minute. The arrhythmatous condition needs to be controlled, as humans cannot withstand this rapid and chaotic beating of the heart. New investigational drugs like Dronedarone(®) are being used. Dronedarone is the most recent antiarrhythmic drugs. It was approved by US-FDA on July 2nd 2009 and is available in the USA as Multaq tablets (400 mg). Dronedarone falls under the category of multiple ion channel blocker. It mainly targets the repolarization currents, making them less active and hence prolonging the action potential duration (APD). Dronedarone also exhibits antiadrenergic activity, thus reducing the pace of the pacemaker. Dronedarone has been proven to be a safer and efficacious AAD, evidenced by both animal and human studies. These studies showed that there was prolongation of the APD and absence of QT interval prolongation with long term administration of the drug. Also there was reduced thyroid hormone receptor expression. Dronedarone is significantly safer and effective in maintaining the sinus rhythm and reducing the ventricular proarrhythmias, justifying it for the long term treatment of atrial fibrillation compared to other antiarrhythmic drugs. |
5,999 | Effects of α-methylnorepinephrine on cardiac function and myocardium at early stage of resuscitation in rabbits. | Recent studies have shown that α2-adrenergic agonists can reduce postresuscitation myocardial injury. This study was undertaken to observe changes of hemodynamics, myocardial injury markers cTnT and cardiac morphology by establishing a cardiopulmonary resuscitation model with rabbits, and to detect whether α-methyl norepinephrine (α-MNE) can reduce the myocardial injury after CPR and improve cardiac function.</AbstractText>Eighteen health rabbits, weighing 2.5-3.5 kg, both male and female, were provided by the Lanzhou Institute of Veterinary Medicine. After setting up a rabbit model of cardiopulmonary resuscitation, 18 rabbits were randomly divided into three groups. The rabbits in group A as an operation-control group were subjected to anesthesia, endotracheal intubation, and surgery without induction of ventricular fibrillation. The rabbits in group B as an epinephrine group were administered with 30 μg/kg epinephrineduring CPR. The rabbits in group C as a MNE group were administered with 100 μg/kg a-MNE during CPR. The left ventricular end-diastolic pressure (LVEDP), left ventricular pressure rise and fall rate (±dp/dt) and serum concentrations of BNP were measured. Statistical package of SPSS 10.0 was used for data analysis and significant differences between means were evaluated by ANOVA.</AbstractText>Compared to group A, the LVEDP of other two groups increased respectively (P<0.01 all), and peak±dp/dt decreased in the other two groups (P<0.01). The increase of LVEDP was lower in group C than in group B (P<0.05), whereas peak±dp/dt was higher in group C than in group B (P<0.05) at the same stage. Compared to group A, the cTnT of the remaining two groups increased, respectively (P<0.01), and peaked at 30 minutes. cTnT was less elevated in group C than in group B (P<0.05) during the same period. In groups B and C, myocardial injury was seen under a light microscope, but the injury in group C was lighter than that in group B.</AbstractText>Methylnorepinephrine can lessen myocardial dysfunction after CPR.</AbstractText> |
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