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5,600 | [Life-threatening brady- and tachyarrhythmias]. | Bradycardic (heart rate<50/min) and tachycardic heart rhythm disturbances (100/min) require rapid therapeutic strategies. Supraventricular tachycardias (SVT) are sinus tachycardia, atrial tachycardia, AV-nodal reentrant tachycardia and tachycardia due to accessory pathways. Mostly SVT are characterized by small QRS complexes (QRS width<0.12 ms). It is essential to evaluate the arrhythmia history, to perform a good physical examination and to exactly analyze the 12-lead electrocardiogram. An exact diagnosis is then possible in >90% of SVT patients. Ventricular tachycardias have a broad QRS complex (>or=0.12 s), ventricular flutter and ventricular fibrillation are associated with chaotic electrophysiologic findings. For acute therapy, we will present the new concept of the "5A" that includes adenosine, adrenaline, ajmaline, amiodarone and atropine. Additional "B, C and D strategies" include betablocking agents, cardioversion as well as defibrillation. The "5A" concept allows a safe and effective antiarrhythmic treatment of all bradycardic and tachycardic arrhythmias as well as asystolia. |
5,601 | Emergency revascularization procedures in patients with acute ST-elevation myocardial infarction due to acute total occlusion of unprotected left main coronary artery: a report of five cases. | Several studies have compared the efficacy of elective coronary artery stenting and coronary artery bypass grafting (CABG) in patients with unprotected left main coronary artery (ULMCA) disease. However, a definite reperfusion modality has yet to be established in ST-elevation myocardial infarction (STEMI) due to acute total occlusion of ULMCA, which has catastrophic clinical results. We presented five patients (3 males, 2 females; mean age 59 years; range 53 to 67 years) with acute anterior STEMI and angiographically documented acute total occlusion of ULMCA. On presentation, all the patients had chest pain and four patients were in cardiogenic shock. All the patients were taken to the catheterization room with minimum delay. Intra-aortic balloon counterpulsation was used during coronary angiography in all the patients. Three patients underwent PCI and, after balloon predilatation, bare-metal stents were implanted and TIMI III flow was achieved. One patient who had atrial fibrillation on admission died on the 14th day of hospitalization after PCI due to pump failure. After diagnostic coronary angiography, two patients were submitted to surgery for emergency CABG. They both died, one within two hours of admission during preparation of the surgical team, and the other on the third postoperative day. Both were in cardiogenic shock on admission. |
5,602 | The influence of left ventricular diameter on left atrial appendage size and thrombus formation in patients with dilated cardiomyopathy. | Patients with dilated cardiomyopathy are considered a high risk group for left ventricular (LV) thrombus formation. However, the left atrial appendage (LAA) might be an additional site for thrombus formation in this patient group. We evaluated the association between LV size and left atrium/LAA size and determined the incidence of spontaneous echo contrast (SEC)/thrombus in the LV, left atrium, and LAA in patients with and without enlarged LV dimensions.</AbstractText>In a prospective design, we examined 45 patients with transthoracic and transesophageal echocardiography. Nineteen patients had an enlarged LV dimension (group 1: LV end-diastolic diameter = or >58 mm), and 26 patients had a normal LV size (group 2). Nonvalvular atrial fibrillation (AF) was present in 13 patients (68.4%) in group 1 and in 14 patients (53.9%) in group 2. Echocardiographic parameters included LV dimension and ejection fraction, left atrial diameter, LAA maximal area, and detection of SEC/thrombus in the LV, left atrium, and LAA.</AbstractText>The two groups were similar with regard to demographic and clinical features. Patients in group 1 had a significantly increased LV end-diastolic diameter (63.5+/-3.8 mm vs. 50.9+/-0.9 mm; p<0.001) and decreased ejection fraction (45.3+/-11.7% vs. 56.0+/-10.2%; p=0.002). Left atrial diameter did not differ significantly, but maximal LAA area was significantly greater in group 1 (4.9+/-2.3 cm2 vs. 3.3+/-0.8 cm2; p=0.002). Among the frequencies of SEC and thrombus in the LV, left atrium, and LAA, only the frequency of thrombus in the LAA was significantly higher in group 1 (36.8% vs. 7.7%; p=0.05). Compared to patients with a normal LV size and AF, the coexistence of AF with dilated LV was significantly associated with a greater LV end-diastolic diameter (p<0.001) and LAA maximal area (p=0.02).</AbstractText>Patients with a dilated LV have a larger LAA and seem to be at a higher risk for LAA thrombus formation.</AbstractText> |
5,603 | Inverted graft insertion technique for apicoaortic bypass. | The proximal anastomosis of the apicoarotic bypass is technically demanding. We describe our novel surgical technique to reinforce the proximal anastomosis of the apicoaortic bypass. After moving circular muscle of the left ventricle (LV) under ventricular fibrillation, an inverted tube graft is inserted into LV through the opening of the apex. Then, end-to-end anastomosis is made with horizontal mattress sutures passing from the inside of the inverted tube graft through the entire thickness of LV muscle and a running suture of the edge of LV muscle and graft. As the tube graft is pulled out from the LV, the anastomosis is completed. This technique permits simple and reliable suture placement without the need for any special device for the proximal anastomosis of the apicoaortic bypass. |
5,604 | [Evolution and thromboembolic complications of the idiopathic peripartal cardiomyopathy at Dakar University Hospital: forward-looking study about 33 cases]. | The aims of this work are to study the nursery futures during idiopathic myocardiopathy of peripartum (IMPP), to measure the prevalence of thromboses and spontaneous contrast during the IMPP and to determine their evolution.</AbstractText>It is about a longitudinal exploratory study carried out with the Aristide-Le-Dantec teaching hospital of Dakar, beginning January 2001 to November 2004, having included 33 patients.</AbstractText>The average age of the patients was 26 years; the average pregnancy was of 3.39 gestures. The signs of cardiac insufficiency were constant and four patients (12%) had presented an ischemic cerebral vascular accident. We had raised an auricular case of fibrillation and tachycardia atrial multifocal. The transthoracic echography (ETT) noted an aspect of hypokinetic myocardiopathy dilated with deterioration of the systolic function of the left ventricle, a thrombus in ten patients (30.3%) and a spontaneous contrast in two cases (6%). The transoesophageal echocardiography (ETO) was superposable with the ETT with regard to dimensions of the cardiac cavities and the presence of thrombus but its sensitivity was higher (100% against 66%) with regard to the detection of contrasts spontaneous. All the patients had the treatment of a congestive heart failure associated to an anticoagulant treatment. The evolution was marked by an improvement of the heart failure. The thrombus and spontaneous contrast had disappeared in all the patients. The absence of anaemia and the presence of spontaneous contrast (p=0.003) were correlated with the presence of thrombosis (p=0.05).</AbstractText>The idiopathic myocardiopathy of the peripartum is a relatively frequent affection in zone Soudano-Sahelian. Occurrence of thromboses is frequent at the time of this affection. Our study confirms the superiority of the echocardiography transoesophageal in the detection of intracardiac spontaneous contrast. The evolution can be favourable subject to a rigorous care and a regular surveillance.</AbstractText>Copyright © 2010 Elsevier Masson SAS. All rights reserved.</CopyrightInformation> |
5,605 | Pravastatin attenuates cardiac dysfunction induced by lysophosphatidylcholine in isolated rat hearts. | Lysophosphatidylcholine (LPC), which accumulates in the ischemic myocardium, is responsible for mechanical and metabolic derangements of hearts, and also contributes to the development of ventricular arrhythmias. We examined the effects of pravastatin on the LPC-induced cardiac dysfunction in isolated rat hearts. Rat hearts were randomly divided into four groups. The groups comprised a control group (n=10), a group treated with LPC (5 microM) (n=20), a group treated with pravastatin (400 ng/ml) (n=10) and a group treated with both LPC and pravastatin (n=20). Our data suggest that, pravastatin possesses some protective profiles against LPC, as manifested by better recovery of cardiac function (improvement in heart rate, left ventricular developed pressure, maximal and minimal first derivatives of left ventricular developed pressure, coronary flow and coronary resistance, less release of biomarkers of cardiac injury (lactate dehydrogenase, creatine kinase-MB and endothelin-1), and attenuation of ventricular arrhythmias (ventricular tachyarrhythmia and ventricular fibrillation). |
5,606 | Comparison of the effects of methadone and heroin on human ether-à-go-go-related gene channels. | Torsades de pointes (TdP) is a life-threatening form of ventricular arrhythmia that occurs under conditions of delayed cardiac repolarization indicated by prolonged QT intervals in ECG recordings. The main mechanism of QT prolongation and TdP is block of the rapid component of the cardiac delayed rectifier K(+) current (I(Kr)), which is encoded by hERG (human ether-à-go-go-related gene). The opioid agonist methadone has previously been demonstrated to inhibit hERG currents, and there are reports of serious cardiac arrhythmias and deaths from TdP and ventricular fibrillation in patients taking methadone. The aim of the present study was to compare the effects of the opioid agonists methadone and heroin (3,6-diacetylmorphine) on hERG currents stably expressed in human embryonic kidney (HEK 293) cells using the whole-cell configuration of the patch-clamp technique. Both methadone and heroin inhibit hERG currents in a concentration-dependent manner. The following values were calculated for IC(50) (concentration causing half-maximal inhibition) and n (the Hill coefficient): 4.8 microM and 0.9 for methadone, 427 microM and 0.7 for heroin. In conclusion, the potency for block of hERG currents is about 100-fold lower for heroin when compared to methadone. |
5,607 | Initial serum glucose level and white blood cell predict ventricular arrhythmia after first acute myocardial infarction. | The aims of this study are to analyze the factors that predispose the occurrence of ventricular arrhythmia (VA) in young patients with a first acute myocardial infarction (AMI) in the emergency department (ED) and to establish predictive implications.</AbstractText>This is a 10-year retrospective cohort study. Patients who were older than 18 years and younger than 45 years with a first attack of AMI were recruited from the ED of 3 university teaching hospitals from January 1, 1998, to December 31, 2007.</AbstractText>Five hundred young patients (472 men and 28 women) who met the inclusion criteria were enrolled. Within these patients, the incidence of life-threatening VA with first attack of AMI was 8% (n = 40). They were categorized into 2 groups: VA attack (n = 40) and non-VA attack (n = 460). In univariable analyses, acute anterolateral ST-segment elevation myocardial infarction (65% vs 47.8%; P = .04), elevate white blood cell (WBC) count (16.4 +/- 3.4 vs 11.5 +/- 3.1 x 10(3)/mm(3); P < .01), and initial serum glucose level (202.6 +/- 90.9 vs 151.9 +/- 64.7 mg/dL; P < .01) were significantly increased in the VA group. Multiple logistic regression model identified WBC count and initial serum glucose level as the significant independent variables in the prediction of VA attack for young patients with first attack of AMI. The receiver operating characteristic area for WBC count and serum glucose level in predicting the risk of VA occurring after AMI was 0.869 and 0.756, respectively.</AbstractText>Initial serum glucose level and WBC may be used as valuable predictors for VA attack in young patients with first AMI.</AbstractText>(c) 2010 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,608 | An entirely subcutaneous implantable cardioverter-defibrillator. | Implantable cardioverter-defibrillators (ICDs) prevent sudden death from cardiac causes in selected patients but require the use of transvenous lead systems. To eliminate the need for venous access, we designed and tested an entirely subcutaneous ICD system.</AbstractText>First, we conducted two short-term clinical trials to identify a suitable device configuration and assess energy requirements. We evaluated four subcutaneous ICD configurations in 78 patients who were candidates for ICD implantation and subsequently tested the best configuration in 49 additional patients to determine the subcutaneous defibrillation threshold in comparison with that of the standard transvenous ICD. Then we evaluated the long-term use of subcutaneous ICDs in a pilot study, involving 6 patients, which was followed by a trial involving 55 patients.</AbstractText>The best device configuration consisted of a parasternal electrode and a left lateral thoracic pulse generator. This configuration was as effective as a transvenous ICD for terminating induced ventricular fibrillation, albeit with a significantly higher mean (+/-SD) energy requirement (36.6+/-19.8 J vs. 11.1+/-8.5 J). Among patients who received a permanent subcutaneous ICD, ventricular fibrillation was successfully detected in 100% of 137 induced episodes. Induced ventricular fibrillation was converted twice in 58 of 59 patients (98%) with the delivery of 65-J shocks in two consecutive tests. Clinically significant adverse events included two pocket infections and four lead revisions. After a mean of 10+/-1 months, the device had successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia.</AbstractText>In small, nonrandomized studies, an entirely subcutaneous ICD consistently detected and converted ventricular fibrillation induced during electrophysiological testing. The device also successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia. (ClinicalTrials.gov numbers, NCT00399217 and NCT00853645.)</AbstractText>2010 Massachusetts Medical Society</CopyrightInformation> |
5,609 | Genetic basis of malignant channelopathies and ventricular fibrillation in the structurally normal heart. | Sudden cardiac death occurs in a minority of patients in the absence of structural or functional abnormalities. In this category, pure electrical heart diseases are responsible for a large number of these unexpected deaths. These conditions include the long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, short QT syndrome (collectively referred to as channelopathies) and idiopathic ventricular fibrillation. This article reviews the current molecular understanding of the electrical diseases of the heart associated with sudden cardiac death, and provides a summary of the causal genes and a flowchart with an overview of the genotype-phenotype correlation of the most common arrhythmia syndromes. |
5,610 | [A patient with aortic valve stenosis and severe obstruction of the left ventricular outflow tract: a diagnostic challenge]. | A 83-year-old male patient was admitted with dyspnoe and paroxysmal atrial fibrillation. A severe aortic stenosis was diagnosed 9 months before.</AbstractText>Echocardiography now revealed severe obstruction of the left ventricular outflow tract, as part of an obstructive cardiomyopathy, mild aortic valve stenosis and mark4d left atrial dilatation.</AbstractText>After spontaneous conversion into sinus rhythm the patient remained asymptomatic and continuing conservative treatment was recommended.</AbstractText>It may be difficult to diagnose the correct components of systolic obstruction when there is both obstructive cardiomyopathy and aortic valve stenosis and thus decide on the optimal management of such a case.</AbstractText>Georg Thieme Verlag KG Stuttgart * New York.</CopyrightInformation> |
5,611 | Induction by direct current pulse versus 50-Hz pacing on ventricular fibrillation and defibrillation. | Ventricular fibrillation (VF) induced by different modes of induction may have different characteristics and defibrillation thresholds. This study compares the cycle lengths and defibrillation of VF induced by direct current (DC) pulses vs 50 Hz.</AbstractText>We compared induction by DC pulses and 50-Hz pacing in this single-centre observational study of 259 consecutive patients with implantable cardioverter defibrillators in 2007-2008. Patients with inadequate defibrillation safety margin (DSM), defined as unsuccessful defibrillation at 25 J, were identified.</AbstractText>Of the 259 patients, 132 underwent induction with DC pulses and 127 with 50-Hz pacing. DC pulses induced VF of shorter cycle lengths (207 ± 16 vs 231 ± 24 ms, p < 0.001) compared to 50-Hz pacing. There were 17 patients (6.6%) with inadequate DSM-13/132 (9.8%) with DC pulse vs 4/127 (3.1%) with 50-Hz pacing (p < 0.001). The induced VF cycle lengths were shorter in patients with inadequate DSM (186 ± 25 vs 221 ± 21 ms, p < 0.001). On multivariate analysis, only the induced VF cycle length (p = 0.002) was independently associated with inadequate DSM.</AbstractText>VF of shorter cycle lengths is independently associated with inadequate DSM. DC pulses are associated with greater proportion of patients with inadequate DSM as it induces VF of shorter cycle lengths compared to 50-Hz pacing.</AbstractText> |
5,612 | A left ventricular epicardial to right ventricular endocardial dominant frequency gradient exists in human ventricular fibrillation. | We hypothesized that in patients with left ventricular dysfunction undergoing implant of a biventricular ICD, the local dominant frequency during early induced ventricular fibrillation would be higher at an epicardial left ventricular position compared to an endocardial right ventricular position.</AbstractText>Patients undergoing implant of a biventricular ICD were studied. During ventricular fibrillation induction, bipolar electrograms were recorded from leads at an epicardial left ventricular position and an endocardial right ventricular position. Overlapping 2-s fast Fourier transforms were obtained for 6 s of ventricular fibrillation. The dominant frequency and organizational index were compared.</AbstractText>Thirty-four patients (20 men, age 64 ± 11 years) underwent 57 inductions of ventricular fibrillation. Eighteen patients had non-ischemic dilated cardiomyopathy and 16 had ischemic dilated cardiomyopathy. The dominant frequency was higher at a lateral epicardial left ventricular position than an apical endocardial right ventricular position in 18 patients with non-ischemic dilated cardiomyopathy (LV epicardial 5.34 ± 0.37 Hz, RV endocardial 5.09 ± 0.41 Hz, p < 0.001), but not in 16 patients with ischemic dilated cardiomyopathy (LV epicardial 4.99 ± 0.57 Hz, RV epicardial 4.87 ± 0.65 Hz, p = 0.094).</AbstractText>In patients with non-ischemic dilated cardiomyopathy, there is a dominant frequency gradient during early ventricular fibrillation induced at ICD testing from the lateral left ventricular epicardium to the apical right ventricular endocardium.</AbstractText> |
5,613 | The molecular mechanism of protective effects of grape seed proanthocyanidin extract on reperfusion arrhythmias in rats in vivo. | Reperfusion arrhythmias (RA) especially ventricular tachycardia (VT) and ventricular fibrillation (VF) remain the most important causes of sudden death following reperfusion. In isolated rat hearts grape seed proanthocyanidin extract (GSPE) had been proved to reduce the incidence of reperfusion-induced VF and VT. However the mechanism of this protection remained unclear. The aim of this study was to elucidate the potential mechanism of this protection of GSPE. The myocardial ischemia reperfusion (IR) model was induced by 30 min coronary occlusion and 120 min reperfusion in open chest anesthetized rats. The ultrastructure of ischemic cardiomyocytes was observed. An isobaric tag labeling for relative and absolute quantification (iTRAQ) proteomics was used to identify differentially expressed membrane proteins. Western blot was performed to verify the results of iTRAQ. The results demonstrated GSPE can significantly reduce the incidence of VT and VF induced by reperfusion in vivo. We identified 92 differentially expressed proteins. Western blot analysis confirmed GSPE increased the expression of Na(+)/K(+)-ATPase alpha1 subunit (p<0.01). We found the subunit distribution of Na(+)/K(+)-ATPase was changed after reperfusion. Na(+)/K(+)-ATPase alpha1 subunit was decreased in IR group (without GSPE-treated) compared to sham group while it was significantly increased in GSPE group. The decrease of free radical generation induced by GSPE may lead to the up-regulation of Na(+)/K(+)-ATPase alpha1 subunit. This change of subunit distribution may lead to the increase of activity of Na(+)/K(+)-ATPase which may result in the protection of GSPE against reperfusion arrhythmias. Our experiments provided new avenues for the treatment of reperfusion arrhythmias. |
5,614 | Fundamental frequency and regularity of cardiac electrograms with Fourier organization analysis. | Dominant frequency analysis (DFA) and organization analysis (OA) of cardiac electrograms (EGMs) aims to establish clinical targets for cardiac arrhythmia ablation. However, these previous spectral descriptions of the EGM have often discarded relevant information in the spectrum, such as the harmonic structure or the spectral envelope. We propose a fully automated algorithm for estimating the spectral features in EGM recordings. This approach, called Fourier OA (FOA), accounts jointly for the organization and periodicity in the EGM, in terms of the fundamental frequency instead of dominant frequency. In order to compare the performance of FOA and DFA-OA approaches, we analyzed simulated EGM, obtained in a computer model, as well as two databases of implantable defibrillator-stored EGM. FOA parameters improved the organization measurements with respect to OA, and averaged cycle length and regularity indexes were more accurate when related to the fundamental (instead of dominant) frequency, as estimated by the algorithm (p < 0.05 comparing f(0) estimated by DFA and by FOA). FOA yields a more detailed and robust spectral description of EGM compared to DFA and OA parameters. |
5,615 | [Effect of beta-adrenoblockers on remodeling of myocardium and adhesive function of endothelium in patients with ischemic heart disease, complicated with chronic heart failure and atrial fibrillation]. | To elucidate effect of adrenoblockers on remodeling of myocardium and adhesive function of endothelium in with ischemic heart disease with chronic heart failure (CHF) and addition of atrial fibrillation (AF).</AbstractText>We included into the study 77 patients with functional class II-III CHF and AF of ischemic genesis randomized in 2 groups, In group 1 were included 40 patients who during 24 weeks used carvedilol at the background of basic therapy, in group 2 - 37 patients receiving metoprolol tartrate. In the work we used clinico instrumental (echocardiography, test with 60 minute walk), immunoenzymatic (soluble intercellular adhesion molecules (sVCAM, SE - selectin) methods of investigation.</AbstractText>Application of both BAB improved clinical state and physical working capacity of patients with CHF and AF. Carvedilol more significantly than metoprolol tartrate prevented remodeling of myocardium, inhibited expression of cellular adhesion molecules. Levels of sE selectin and VCAM 1 decreased under action of carvedilol.</AbstractText>Carvedilol in long term therapy of CHF with AF exerts substantial influence on adhesive function of endothelium and improves hemodynamics.</AbstractText> |
5,616 | Prevalence of atrial fibrillation in hospitalized patients over 40 years old: ten-year data from the People's Hospital of Peking University. | The risk factors for atrial fibrillation (AF) are complicated and multifactorial. In the present study we investigated the prevalence of atrial fibrillation in China.</AbstractText>The inpatient medical records of patients over 40 years with AF in the People's Hospital of Peking University from October 1998 to September 2008 were retrospectively analysed in the present study. All patients were divided into AF and non-AF groups. Their clinical characteristics were compared and the risk factors were also investigated.</AbstractText>Multivariate analysis demonstrated that AF was independently associated with rheumatic heart disease (odds ratio (OR), 16.53; 95% confidence interval (CI), 8.66-31.54; P < 0.0 1), congestive heart failure (OR, 5.13; 95% CI, 3.14-8.37; P < 0.01), hyperthyroidism (OR, 2.65; 95% CI, 1.71-4.09; P < 0.01), age (OR, 1.74; 95% CI, 1.46-2.07; P < 0.01), low serum albumin (OR, 2.02; 95% CI, 1.43-2.84; P < 0.01), hypertension (OR, 1.48; 95% CI, 1.22-1.80; P < 0.01), high serum uric acid (OR, 1.42; 95% CI, 1.18-1.70; P < 0.01), male sex (OR, 0.62; 95% CI, 0.52-0.74; P < 0.01), and idiopathic cardiomyopathy (OR, 1.98; 95% CI, 1.06-3.71; P = 0.03).</AbstractText>The risk factors for prevalence of AF in China mainly include rheumatic heart disease, heart failure, hyperthyroidism, hypertension, idiopathic cardiomyopathy, older age and male sex. Furthermore, an independent relationship between low serum albumin, high serum uric acid and AF was also confirmed.</AbstractText> |
5,617 | Admission glucose level and in-hospital outcomes in diabetic and non-diabetic patients with acute myocardial infarction. | Hyperglycemia on admission is a predictor of unfavorable prognosis in patients with acute myocardial infarction (AMI). Data concerning associations between elevated glucose level on admission and other in-hospital complications are still limited.</AbstractText>A total of 607 AMI patients with complete admission glucose data in the Krakow Registry of Acute Coronary Syndromes were identified and were stratified according to glucose admission level.</AbstractText>A total of 71.5% of patients were with admission glucose level <7.8 mmol/l, 17.6% of patients with 7.8-11.0 mmol/l, and 10.9% of patients with ≥11.1 mmol/l. In-hospital mortality for patients treated conservatively was higher in patients with higher admission glucose (8.0 vs. 25.0 vs. 39.1%, respectively, P < 0.0001), and significant mortality difference was confirmed both for diabetic and non-diabetic patients. Admission hyperglycemia was associated with increased risk of ventricular tachycardia/ventricular fibrillation, atrial fibrillation, second to third atriventricular block, pulmonary oeadema, but not ischemic stroke and blood transfusion during index hospital stay.</AbstractText>Elevated admission glucose levels are associated with increased risk of life-threatening complications, especially arrhythmias in diabetic and non-diabetic AMI patients. This increased risk of complications is one of the possible explanations for the elevated in-hospital mortality in AMI patients presenting with hyperglycemia.</AbstractText> |
5,618 | Acquired noncompaction associated with coronary heart disease and myopathy. | In a 77-year-old man with a history of arterial hypertension, coronary heart disease, dilative cardiomyopathy, mitral and tricuspid insufficiency, arteriovenous block III, implantation of a pacemaker, atrial fibrillation, and heart failure, left ventricular hypertrabeculation (LVHT) was detected on transthoracic echocardiography during hospitalization for worsening heart failure. Revision of previous echocardiography did not show LVHT in any of the previous investigations why LVHT was interpreted as acquired. The additional presentation with bilateral ptosis, madarosis (absent eyelashes), bilateral hypoacusis, sore neck muscles, absent tendon reflexes, weakness for foot extension, ataxic stance, and recurrently elevated creatine kinase with normal troponin-T suggested a metabolic myopathy. Autopsy after death resulting from intractable heart failure, 17 months later, confirmed severe coronary heart disease and LVHT in the apex. The case confirms that LVHT may be acquired in single cases with neuromuscular disease and may represent an adaptive mechanism of an impaired myocardium. |
5,619 | Risk factors for recurrent heart failure events in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). | Risk Factors for Recurrent Heart Failure.</AbstractText>This study was designed to identify risk factors for recurrent heart failure (HF) events in patients with ischemic left ventricular dysfunction enrolled in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II).</AbstractText>The Prentice, Williams, and Peterson (PWP) statistical model was utilized to identify and compare risk factors for 1 or ≥ 2 HF hospitalizations among 1,218 patients with ischemic left ventricular dysfunction enrolled in the MADIT-II trial. Risk factors for a first HF hospitalization included treatment with an ICD (HR = 1.31; P = 0.05), New York Heart Association class > II (HR = 1.95; P < 0.001), female gender (HR = 1.38; P = 0.05), atrial fibrillation (HR = 1.90; P = 0.001), QRS >120 ms (HR = 1.41; P = 0.01), diabetes mellitus (HR = 1.51; P = 0.003), heart rate ≥ 80 (HR = 1.35; P = 0.04), diuretic therapy (HR = 1.82; P < 0.001), and the presence of prerenal azotemia (defined as blood urea nitrogen:creatinine > 20; HR = 1.45; P = 0.01). In contrast, prerenal azotemia was the only risk factor that was independently associated with a significant increase in the risk of ≥ 2 HF hospitalizations (HR = 1.52; P = 0.027). The occurrence of 1 HF event after enrollment was associated with a 2.8-fold (P < 0.001) increase in the risk of death, whereas after the occurrence of a second event there was a 6.7-fold (P < 0.001) increase in the risk of subsequent mortality.</AbstractText>In MADIT-II, prerenal azotemia was the only significant and independent risk factor for HF progression after a first event, and recurrent HF was the most powerful predictor of mortality. These findings stress the importance of identifying risk factors for HF progression among patients who receive an ICD for primary prevention.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,620 | J-wave disappearance immediately after an episode of ventricular fibrillation in a patient with resuscitated sudden cardiac death and Brugada syndrome. | Early repolarization (ER) abnormalities in the inferior-lateral leads are a matter of intense scientific debate because of their demonstrated association with Brugada syndrome (BS) and idiopathic ventricular fibrillation (VF). To add fuel to the fire, we present a case in which ER abnormalities are associated with BS but in which, more importantly, they were shown to be transient and strictly correlated with an episode of VF. |
5,621 | Safety of remote magnetic navigation in patients with pacemakers and implanted cardioverter defibrillators. | Remote magnetic catheter navigation (MNS) has been shown to be feasible and safe for radiofrequency catheter ablation of various cardiac arrhythmias. However, its safety in patients with implanted pacemakers or cardioverter-defibrillators has not yet been studied.</AbstractText>This retrospective case series study intends to assess the acute and short-term safety of remote MNS in patients with implanted pacemakers or cardioverter-defibrillators.</AbstractText>Between January 2008 and June 2009, a total of 31 patients with implanted pacemakers (n = 5) or cardioverter-defibrillators (n = 26) underwent 32 catheter ablation procedures using the remote MNS. Baseline pacing thresholds, sensed amplitudes, pacing and, if available, shock impedances as well as battery status were measured in all devices before, immediately after, and 1-3 months after catheter ablation.</AbstractText>After ablation, no statistically significant difference in atrial sensing (2.7 ± 1.5 mV vs 3.1 ± 1.9 mV, P = 0.18) and impedance (457 ± 104 Ω vs 449 ± 101 Ω, P = 0.37) were observed. After ablation, no statistically significant difference in right ventricular sensing (10.4 ± 3.8 mV vs 10.9 ± 4.9 mV, P = 0.43) and impedance (535 ± 118 Ω vs 534 ± 120 Ω, P = 0.913) were observed. No changes in pacing threshold could be observed in all but 2 patients with biventricular cardioverter-defibrillators who underwent ventricular tachycardia ablation in lateral wall of left ventricle near the implanted epicardial electrode.</AbstractText>Ablation procedures using remote MNS can be performed safely in patients with implanted devices with no significant effects on device system integrity. Long endocardial ablation close to the insertion site of the implanted epicardial left ventricular leads can affect the pacing and/or sensing characteristics of these electrodes.</AbstractText>© 2010 Wiley Periodicals, Inc.</CopyrightInformation> |
5,622 | Post-conditioning with cyclosporine A fails to reduce the infarct size in an in vivo porcine model. | Cyclosporine A has generated intense interest in the field of cardioprotection due to its ability to protect the mitochondria at reperfusion by blocking the opening of the mitochondrial permeability transition pore. The aim of our study was to examine the cardioprotective effect of Sandimmun, a clinically available formulation of cyclosporine A, in an in vivo large mammal model.</AbstractText>Forty-eight pigs were randomly allocated to one of three groups: (i) Control group (Con, n=19), (ii) Cyclosporine group, (Cyclo, n=19) Sandimmun 10 mg/kg i.v. bolus 5 min before reperfusion and (iii) Pre-conditioning group (Precon, n=10) two cycles of 10 min ischemia interspersed with 30-min reperfusion. The study was further sub-divided into a metabolic protocol, evaluating myocardial metabolism by measuring changes in the interstitial lactate concentration, and a coronary flow protocol. All animals were subjected to 40 min of left anterior descending coronary artery occlusion, followed by 180 min of reperfusion before histochemical staining and assessment of infarct size by planimetry.</AbstractText>Infarct sizes were measured as: Con 51.4 +/- 16.5%, Cyclo 47.3 +/- 15.7% and Precon 2.4 +/- 3.6%, with no significant difference between the Con and Cyclo groups but a highly significant difference between the Precon and Cyclo and Con groups (P<0.0001 for both comparisons). In the Cyclo group, the interstitial lactate concentration was significantly increased compared with the Con group at 6-min reperfusion, although significantly lower at 14 min presumably due to accelerated washout.</AbstractText>In this large animal model, a 10 mg/kg bolus administration of Sandimmun 5 min before reperfusion did not reduce the infarct size.</AbstractText> |
5,623 | Unexpected low prevalence of atrial fibrillation in cryptogenic ischemic stroke: a prospective study. | Ischemic stroke is a frequent pathology with high rate of recurrence and significant morbidity and mortality. There are several causes of stroke, affecting prognosis, outcomes, and management, but in many cases, the etiology remains undetermined. We hypothesized that atrial fibrillation was involved in this pathology but underdiagnosed by standard methods. The aim of the study was to determine the incidence of atrial fibrillation in cryptogenic ischemic stroke by using continuous monitoring of the heart rate over several months. The secondary objective was to test the value of atrial vulnerability assessment in predicting spontaneous atrial fibrillation.</AbstractText>We prospectively enrolled 24 patients under 75 years of age, 15 men and 9 women of mean age 49 years, who within the last 4 months had experienced cryptogenic stroke diagnosed by clinical presentation and brain imaging and presumed to be of cardioembolic mechanism. All causes of stroke were excluded by normal 12-lead ECG, 24-h Holter monitoring, echocardiography, cervical Doppler, hematological, and inflammatory tests. All patients underwent electrophysiological study. Of the patients, 37.5% had latent atrial vulnerability, and 33.3% had inducible sustained arrhythmia. Patients were secondarily implanted with an implantable loop recorder to look for spontaneous atrial fibrillation over a mean follow-up interval of 14.5 months. No sustained arrhythmia was found. Only one patient had non-significant episodes of atrial fibrillation.</AbstractText>In this study, symptomatic atrial fibrillation or AF with fast ventricular rate has not been demonstrated by the implantable loop recorder in patients under 75 years with unexplained cerebral ischemia. The use of this device should not be generalized in the systematic evaluation of these patients. In addition, this study attests that the assessment of atrial vulnerability is poor at predicting spontaneous arrhythmia in such patients.</AbstractText> |
5,624 | Ventricular fibrillation induced by radiofrequency ablation for slow ventricular tachycardia associated with left ventricular dysfunction. | A 59-year-old man with premature ventricular contractions (PVCs) and slow ventricular tachycardia (VT) underwent electrophysiologic testing. The left ventricular ejection fraction was 27%. Activation mapping showed the site of earliest activation to be the posterolateral site of the right ventricle inflow tract, and we considered this to be the focal mechanism underlying the PVCs/slow VT. Radiofrequency current delivered at this site induced a cluster of rapid ventricular beats (sustained VT) with the same QRS morphology as the PVCs, followed by ventricular fibrillation. The PVC/VT focus might have served as an abnormal automatic trigger and driver for the ventricular fibrillation. |
5,625 | Mechanisms of defibrillation. | Electrical shock has been the one effective treatment for ventricular fibrillation for several decades. With the advancement of electrical and optical mapping techniques, histology, and computer modeling, the mechanisms responsible for defibrillation are now coming to light. In this review, we discuss recent work that demonstrates the various mechanisms responsible for defibrillation. On the cellular level, membrane depolarization and electroporation affect defibrillation outcome. Cell bundles and collagenous septae are secondary sources and cause virtual electrodes at sites far from shocking electrodes. On the whole-heart level, shock field gradient and critical points determine whether a shock is successful or whether reentry causes initiation and continuation of fibrillation. |
5,626 | [Study on effect of total flavonoids from Scutellaria amoena on experimental arrhythmia]. | To observe the effect of total flavonoids from Scutellaria amoena on the experimental arrhythmia.</AbstractText>Experimental animals anesthetized with 10% chloral hydrate were evenly randomized into control group, positive control group, and low-dose, middle-dose and high-dose total flavonoids groups. The experimental arrhythmia ouabain-induced in guinea pigs and barium chloride or calcium chloride-induced in rats were observed and detected respectively. The result was converted into cumulative dosage of ouabain, in guinea pig model. In rat model, the duration of arrhythmia were detected.</AbstractText>hold dosage of ventricular premature heat (VP) and ventricular fibrillation( VF) ouabain-induced in guinea pigs was markedly elevated, and the duration of ventricular tachycardia (VT) barium chloride-induced and VF calcium chloride-induced in rats was postponed by total flavonoids from S. amoena.</AbstractText>Total flavonoids from S. amoena has obvious protective effect on drug-induced arrhythmia.</AbstractText> |
5,627 | New standards in hypertension and cardiovascular risk management: focus on telmisartan. | Blockade of the renin-angiotensin system is an important approach in managing high blood pressure, and has increasingly been shown to affect cardiovascular disease processes mediated by angiotensin II throughout the cardiovascular and renal continua. Telmisartan is an angiotensin II receptor blocker (ARB) displaying unique pharmacologic properties, including a longer half life than any other ARB, that result in large and sustained reductions of blood pressure. In patients with mild-to-moderate hypertension, telmisartan has proved superior to other antihypertensive agents (valsartan, losartan, ramipril, perindopril, and atenolol) in controlling blood pressure particularly towards the end of the dosing interval. There is also clinical evidence that telmisartan reduces left ventricular hypertrophy, reduces arterial stiffness and the recurrence of atrial fibrillation, and confers renoprotection. The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) study has demonstrated that telmisartan has similar cardiovascular protective effects to ramipril in a large, high-risk patient population but was better tolerated. The powerful and sustained blood pressure control apparent in clinical trials, together with cardiovascular protection and tolerability demonstrated in ONTARGET means that telmisartan may be a preferred option for patients with hypertension. |
5,628 | Extending the boundaries of cardiac resynchronization therapy: efficacy in atrial fibrillation, New York heart association class II, and narrow QRS heart failure patients. | Large-scale clinical trials have demonstrated the benefits of cardiac resynchronization therapy (CRT) in patients with New York Heart Association (NYHA) Class III/IV heart failure, systolic left ventricular dysfunction, and a wide QRS. However, additional patient groups may also benefit from CRT.</AbstractText>We meta-analyzed clinical benefits of CRT in heart failure patients with narrow QRS, atrial fibrillation (AF) and NYHA Class II symptoms. Thirteen trials of 2882 patients contributed to this meta-analysis. In the narrow versus wide QRS group comparison, no difference in benefit was observed for change in left ventricular ejection fraction (standardized mean difference [SMD] 0.30, 95% confidence interval [CI] -0.37 to 0.97) or left ventricular end systolic volume (SMD 0.30, 95% CI -1.14 to 1.74). The benefit was greater in the wide QRS group for the 6-minute walk test (SMD 1.27, 95% CI 0.59 to 1.96) and NYHA class improvement (SMD 1.24, 95% CI 0.72 to 1.75). In the atrial fibrillation (AF) versus sinus rhythm (SR) group comparison, no difference in benefit was observed for change in left ventricular ejection fraction (SMD -0.38, 95% CI -1.28 to 0.53) or NYHA improvement (SMD 0.32, 95% CI -0.77 to 1.40). In the NYHA II versus NYHA III/IV group comparison, no difference in benefit was observed for change in left ventricular end diastolic diameter (SMD 0.05, 95% CI -0.94 to 1.05) or left ventricular end systolic diameter (SMD 0.74, 95% CI -1.98 to 3.46).</AbstractText>Large-scale clinical outcome trials of CRT are warranted in heart failure patients with narrow QRS, AF, and NYHA II, given the similar benefits observed to those with wide QRS, SR, and NYHA III/IV for many parameters.</AbstractText> |
5,629 | Usefulness of left ventricle dyssynchrony assessment before cardiac resynchronization implantation. | A number of trials have demonstrated the effect of cardiac resynchronization therapy (CRT) on functional improvement and reversed left ventricle remodeling. Meeting contemporary guidelines approximately 30- 40% of patients do not respond to CRT (non-responders).</AbstractText>To quantify the predictive ability of basal QRS width and basal echocardiographic parameters of left ventricle contraction dyssynchrony in our group of CRT patients. To compare effectiveness of these parameters assessment in patients with ischemic (iCMP) and non-ischemic cardiomyopathy (niCMP) and with sinus rhythm (SR) and atrial fibrillation (AF).</AbstractText>194 patients after successful introduction of CRT device were evaluated. Evaluation of NYHA function class, QRS width and echocardiographic parameters including parameters of left ventricle contraction dyssynchrony (SPWMD: septal-to-posterior wall motion delay, Ts-sep-lat: time interval between maximum of systolic movement of septum and lateral wall using tissue Doppler imaging, IVMD: interventricular mechanical delay) performed before implantation and 3 months after implantation of CRT device.</AbstractText>Responder (improved in NYHA class after CRT) rate was 61%. SR patients showed higher benefit compared to AF patients (responder rate 63% vs. 52%, p<0.05). Narrowing of QRS width after CRT was observed only in responders. SPWMD and Ts-sep-lat decreased after CRT in all subgroups. SPWMD dyssynchrony (SPMWD > or = 130 ms) reduction after CRT was more expressed in niCMP population. Ts-sep-lat dyssynchrony (Ts-sep-lat > or = 65 ms) reduction after CRT was more expressed in SR patients. IVMD (IVMD > or = 60 ms) remained unchanged in average, but significant decrease was observed in responders and significant increase in non-responders. QRS width, SPWMD and Ts-sep-lat showed moderate sensitivity but poor specificity to predict CRT benefit. QRS width > or = 150 ms in niCMP patients showed higher sensitivity to predict CRT effect compared to iCMP patients (91%, 65% respectively). IVMD showed poor sensitivity but good specificity to predict CRT benefit. IVMD in SR patients (compared to AF patients) showed higher specificity to predict CRT effect (90%, 63% respectively).</AbstractText>None of tested left ventricle contraction dyssynchrony parameters showed good sensitivity and specificity to predict CRT benefit. QRS width as a predictor factor was more beneficial in non-ischemic patients and IVMD in sinus rhythm patients.</AbstractText> |
5,630 | Left atrial asynchrony is a major predictor of 1-year recurrence of atrial fibrillation after electrical cardioversion. | The level of atrial mechanical asynchrony may vary within the atrial fibrillation population and this may have pathophysiological relevance.</AbstractText>We sought to verify whether the degree of left-atrial mechanical asynchrony associated with atrial fibrillation is a predictor of arrhythmia recurrence after restoration of sinus rhythm with electrical cardioversion.</AbstractText>Left atrial volume was calculated, whereas two-dimensional (2D) strain (speckle tracking technique) was used to estimate peak and standard deviation (SD) of time-to-peak of deformation of six segments arbitrarily identified along the perimeter of the cavity, imaged in apical four-chamber view. Left atrial mechanical asynchrony was quantified according to quartiles of time-to-peak SD assuming that larger values would identify higher grades of asynchrony. A total of 130 patients undergoing cardioversion for atrial fibrillation were prospectively enrolled. Time-to-peak SD was inversely related with peak strain (P < 0.001). No differences were observed among groups in terms of clinical, therapeutical and additional echocardiographic variables. At 1-year atrial fibrillation was observed in 53% of patients, with time-to-peak SD linearly related to atrial-fibrillation recurrence (P = 0.014). At multivariate analysis only time-to-peak SD (P = 0.032), but not atrial volume (P = 0.075), was identified as an independent predictor of fibrillation recurrence.</AbstractText>This is the first study showing that left atrial asynchrony, quantified as time-to-peak SD of regional atrial strains before electrical cardioversion, is a major independent predictor of fibrillation recurrence in patients back to sinus-rhythm postprocedure.</AbstractText> |
5,631 | Myxoid adrenal cortical carcinoma presenting as primary hyperaldosteronism: case report and review of the literature. | The authors report a case of myxoid adrenal cortical carcinoma (ACC) clinically manifesting as primary hyperaldosteronism. The 82-year-old female patient had a history of hypertension and was sent to the emergency room because of change in consciousness. Ventricular fibrillation occurred, and severe hypokalemia was found. Increased renal loss of potassium, high serum aldosterone level, low renin activity, and a huge tumor in the left suprarenal area were revealed when tests were conducted to determine the cause of her hypokalemia. Left adrenalectomy was performed. The tumor measured 13 cm in diameter and showed a heterogeneous cut surface with gelatinous material. Microscopically, the lesion was composed of polygonal cells with eosinophilic cytoplasm and arranged in arborizing cords in a myxoid background. Capsular and vascular invasion were observed. The tumor stained positive for synaptophysin, melan-A, vimentin, and α-inhibin but negative for cytokeratin. A primary myxoid ACC was diagnosed, which is a rare histological variant. The authors review 13 other reported cases. Most of these were functional tumors causing Cushing syndrome, and only 2 cases presented as primary hyperaldosteronism. All cases had similar microscopic and immunohistochemical features. Distal metastases and local recurrence were not uncommon. Close clinical follow-up is imperative. |
5,632 | Overview of electrocardiographic findings and clinical presentation of common cardiac arrhythmias. | To review the components and interpretation of the 12-lead electrocardiogram (ECG) and compare and contrast the ECG waveforms and clinical presentation associated with major cardiac arrhythmias.</AbstractText>A 12-lead ECG reflects the electrical activity of the heart from many different perspectives, and individual leads may reveal conduction disturbances and disorders in a particular area of the heart. Components of the ECG complex include the P wave, QRS complex, and T wave. The timing and amplitude of ECG waveforms provide valuable information about heart rate and rhythm. This information can be used in conjunction with clinical signs and symptoms to differentiate between major arrhythmias, including atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation.</AbstractText>The monitoring of drug therapies used to treat arrhythmias is facilitated by an understanding of ECG interpretation and the typical clinical characteristics of major cardiac arrhythmias.</AbstractText> |
5,633 | Pharmacotherapeutic decision-making for patients with atrial fibrillation. | To discuss the therapeutic goals in patients with atrial fibrillation (AF); antithrombotic, rate-control, and rhythm-control medications used in these patients; rationale for choosing between rate-control and rhythm-control strategies; and safety, efficacy, and patient-specific considerations in choosing among established antiarrhythmic medications for these patients.</AbstractText>The three primary goals for patients with AF are prevention of thromboembolic stroke, heart rate control, and rhythm control. Warfarin is more effective than aspirin for stroke prevention in patients with AF, and it is recommended for patients at high risk for stroke. However, warfarin is underused, especially in elderly patients. Diltiazem, verapamil, beta-blockers, digoxin, and amiodarone may be used for rate control; the choice among these agents is based on the patient's blood pressure and the presence of certain underlying diseases. Rhythm-control strategies for patients with AF offer no advantage over rate-control strategies in terms of mortality or quality of life, and they are associated with a higher rate of hospitalization. Exercise tolerance is greater with rhythm control, however. The choice among antiarrhythmic agents for maintenance of sinus rhythm after cardioversion is based on safety, efficacy, and the presence of underlying structural heart disease (e.g., heart failure, coronary artery disease, hypertension with or without left ventricular hypertrophy) and renal impairment.</AbstractText>Careful consideration of patient-specific characteristics and the differences in safety and efficacy among antithrombotic, rate-control, and rhythm-control medications is needed to optimize treatment of and outcomes in patients with AF.</AbstractText> |
5,634 | First responder resuscitation teams in a rural Norwegian community: sustainability and self-reports of meaningfulness, stress and mastering. | Training of lay first responder personnel situated closer to the potential victims than medical professionals is a strategy potentially capable of shortening the interval between collapse and start of cardiopulmonary resuscitation (CPR) in cases of out-of-hospital cardiac arrest. In this study we trained lay first responders personnel in basic life support (BLS) and defibrillation for cases of cardiac arrest and suspected acute myocardial infarction (AMI).</AbstractText>Forty-two lay first responders living in remote areas or working in industries in the island community of Austevoll, Western Norway, were trained in CPR and defibrillation. We placed particular emphasis on the first responders being able to defibrillate a primary ventricular fibrillation (PVF) in patients with AMI. The trainees were organised in four teams to attend victims of AMI and cardiac arrest while awaiting the arrival of the community emergency medical services. The purpose of the study was to find out whether the teams were able to function during the five-year study project, and to examine whether lives could be saved. The first responders completed questionnaires each year on their experiences of participation. Data on the medical actions of the teams were also collected.</AbstractText>By the end of the project all groups were functioning. The questionnaires evidenced a reasonable degree of motivation and self-evaluated competence in both types of group organisation, but in spite of this attrition effects in the first responders were considerable. The first responders were called out on 24 occasions, for a total of 17 patients. During the study period no case of PVF occurred after the arrival of the first responders, and the number of AMIs was very low, strongly deviating from what was anticipated. No lives were saved by the project.</AbstractText>The teams were sustained for almost five years without any significant deterioration of self-reported stress or mastering, but still showed attrition effects. Evaluated as a medical project the intervention was not successful, but the small scale prevents us from drawing firm conclusions on this aspect.</AbstractText> |
5,635 | In-treatment reduced left atrial diameter during antihypertensive treatment is associated with reduced new-onset atrial fibrillation in hypertensive patients with left ventricular hypertrophy: The LIFE Study. | It is unclear whether improvement of left atrial (LA) and ventricular (LV) structure results in reduction in new-onset atrial fibrillation (AF). The aim of the present study was to examine whether changes in-treatment LA diameter were related to changes in risk of new-onset AF.</AbstractText>We followed 939 hypertensive patients with electrocardiographic LV hypertrophy randomized to atenolol or losartan-based regimens in the LIFE Study for a mean of 4.8 years with echocardiograms at enrolment and annually during treatment.</AbstractText>New-onset AF occurred in 46 patients (10.2/1000 patient-years of follow-up). At baseline, patients with new-onset AF were older, had higher systolic blood pressure and heart rate as well as higher prevalence of LA dilatation, but had similar prevalences of LV hypertrophy and mitral or aortic valve disease. In univariate Cox analysis baseline LA diameter (HR=4.67 per cm increase [95% CI 2.86-7.65], p<0.001) and LV mass index (HR=1.11 per 10 g/m(2) increase [95% CI 1.02-1.22], p<0.05) both predicted new-onset AF. In multivariate analysis, increased baseline LA diameter increased the risk of new-onset AF (HR=5.16 per cm [95% CI 2.85-9.35], p<0.001) whereas reduction of in-treatment LA diameter reduced the risk (HR=0.21 per cm lower LA diameter during treatment [95% CI 0.14-0.32], p<0.001) with adjustment for in-treatment LV mass in-treatment systolic blood pressure, age and Framingham risk score.</AbstractText>LA diameter at baseline and during antihypertensive treatment were equally strong predictors of new-onset AF independent of the level of arterial pressure, LV mass and other covariates. Prevention of AF during antihypertensive treatment may be improved by antihypertensive therapy that reduces LA size in addition to controlling blood pressure.</AbstractText> |
5,636 | Challenging the superiority of amiodarone for rate control in Wolff-Parkinson-White and atrial fibrillation. | The objective of this review is to explore and challenge the superiority of amiodarone for rate control in Wolff-Parkinson-White syndrome and concomitant atrial fibrillation (WPW-AF). The current recommendation for pharmacological treatment of this condition is amiodarone. A review of the past 25 years of literature finds several studies that identify a small risk of ventricular fibrillation secondary to amiodarone administration for rate control in WPW-AF. Additionally, the literature supports the safe and effective use of procainamide for rate control in WPW-AF. This review concludes that amiodarone is not superior to procainamide in rate control for WPW-AF, and may be dangerous. |
5,637 | Dronedarone in patients with congestive heart failure: insights from ATHENA. | Dronedarone is a new multichannel blocking antiarrhythmic drug for treatment of atrial fibrillation (AF). In patients with recently decompensated congestive heart failure (CHF) and depressed LV function, the drug was associated with excess mortality compared with a placebo group. The present study aimed to analyse in detail the effects of dronedarone on mortality and morbidity in AF patients CHF.</AbstractText>We performed a post hoc analysis of ATHENA, a large placebo-controlled outcome trial in 4628 patients with paroxysmal or persistent AF, to evaluate the relationship between clinical outcomes and dronedarone therapy in patients with stable CHF. The primary outcome was time to first cardiovascular (CV) hospitalization or death. There were 209 patients with NYHA class II/III CHF and a left ventricular ejection fraction < or =0.40 at baseline (114 placebo, 95 dronedarone patients). A primary outcome event occurred in 59/114 placebo patients compared with 42/95 dronedarone patients [hazard ratio (HR) 0.78, 95% CI = 0.52-1.16]. Twenty of 114 placebo patients and 12/95 dronedarone patients died during the study (HR 0.71, 95% CI = 0.34-1.44). Fifty-four placebo and 42 dronedarone patients were hospitalized for an intermittent episode of NYHA class IV CHF (HR = 0.78, 95% CI = 0.52-1.17).</AbstractText>In this post-hoc analysis of ATHENA patients with AF and stable CHF, dronedarone did not increase mortality and showed a reduction of CV hospitalization or death similar to the overall population. However, in the light of the ANtiarrhythmic trial with DROnedarone in Moderate to severe CHF Evaluating morbidity DecreAse study, dronedarone should be contraindicated in patients with NYHA class IV or unstable NYHA classes II and III CHF.</AbstractText> |
5,638 | Cardiac arrest outside and inside hospital in a community: mechanisms behind the differences in outcome and outcome in relation to time of arrest. | The aim was to compare characteristics and outcome after cardiac arrest where cardiopulmonary resuscitation was attempted outside and inside hospital over 12 years.</AbstractText>All out-of-hospital cardiac arrests (OHCAs) in Göteborg between 1994 and 2006 and all in-hospital cardiac arrests (IHCAs) in 1 of the city's 2 hospitals for whom the rescue team was called between 1994 and 2006 were included in the survey.</AbstractText>The study included 2,984 cases of OHCA and 1,478 cases of IHCA. Patients with OHCA differed from those with an IHCA; they were younger, included fewer women, were less frequently found in ventricular fibrillation, and were treated later. If patients were found in a shockable rhythm, survival to 1 month/discharge was 18% after OHCA and 61% after IHCA (P < .0001). Corresponding values for a nonshockable rhythm were 3% and 21% (P < .0001). Survival was higher on daytime and weekdays as compared with nighttime and weekends after IHCA but not after OHCA. Among patients found in a shockable rhythm, a multivariate analysis considering age, gender, witnessed status, delay to defibrillation, time of day, day of week, and location showed that IHCA was associated with increased survival compared with OHCA (adjusted odds ratio 3.18, 95% CI 2.07-4.88).</AbstractText>Compared with OHCA, the survival of patients with IHCA increased 3-fold for shockable rhythm and 7-fold for nonshockable rhythm in our practice setting. If patients were found in a shockable rhythm, the higher survival after IHCA was only partly explained by a shorter treatment delay. The time and day of CA were associated with survival in IHCA but not OHCA.</AbstractText>2010 Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,639 | Uni- or bi-ventricular hypertrophy and susceptibility to drug-induced torsades de pointes. | Cardiac hypertrophy is an independent risk factor for torsades de pointes (TdP), a polymorphic ventricular tachycardia that is often drug-induced, that may evolve into ventricular fibrillation and sudden death. Therefore this study was designed to determine if right (RVH), left (LVH), or biventricular (BVH) hypertrophy increases susceptibility to drug-induced TdP.</AbstractText>Rabbits were separated into 4 groups: control or RVH, LVH, BVH (studied 8weeks after banding of one or both great arteries). ECGs were recorded continuously under anesthesia after baseline and after rabbits received escalating doses of torsadogens (dofetilide, clofilium and terfenadine) or non-torsadogens (cilobradine, diltiazem and vehicle). The following parameters were measured [RR, PQ, QRS and QT] or calculated [QTc (F), short term variability of QT interval].</AbstractText>Generally, torsadogenicity for the compounds tested was dofetilide>clofilium>terfenadine, and there was no TdP following cilobradine, diltiazem or vehicle. In general the susceptibility to TdP was RVH>BVH>LVH>control. Rabbits with RVH developed TdP much more prevalently than for those with either LVH or BVH (p<0.05). At the low dose of dofetilide, LVH was actually protective.</AbstractText>Rabbits with any form of hypertrophy develop prolongation of QT, QTc and increased QT instability. Rabbits with any form of hypertrophy are more prone to arrhythmia than normals in response to known torsadogens.</AbstractText>2010 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,640 | K+ channels in the heart: new insights and therapeutic implications. | K+ channels in the heart shape the cardiac action potential, and many existing drugs can inhibit or activate these currents. In particular, their potential therapeutic benefit has been explored in the treatment and prevention of abnormal heart rhythm. Their use in the management of malignant ventricular arrhythmias has been disappointing and is frequently complicated by proarrhythmia. However, K+ channel-blocking drugs developed for supraventricular rhythm problems, in particular atrial fibrillation, may be more successful. Agents currently in use also have a high incidence of cardiac and other side effects. Thus, the field is moving to a strategy targeting K+ channels that are selectively expressed in the atria, and this is particularly appealing to ameliorate ventricular proarrhythmia. Drugs targeting I(Kur) (K(v)1.5), and to a lesser extent I(KACh) (Kir3.1/3.4), are in various stages of development. |
5,641 | The differential method of phase space matrix for AF/VF discrimination application. | The advances in electrocardiographic (ECG) technology have facilitated the development of numerous successful clinical applications and commercial monitoring products for diagnosing disease and monitoring health. All of these demand the development of smart algorithms and computational resources for the real-time, early indication of critical cardiac conditions. This study presents the development of a Complex Phase Space Difference (CPSD) algorithm with differential method to analyze spatial and temporal changes in reconstructed phase space matrix, and derives an index for real-time monitoring. We used total of 5306 data segments from MIT-BIH, CU, and SCDH databases and clinical trial data to determine the optimal working parameters and verified the classification capability by using a quantitative index of this algorithm. With threshold values set to 2.0 and 6.0, this method can successfully differentiate normal sinus rhythm (NSR) signals (1.48+/-0.21), low risk of atrial fibrillation (AF) signals (3.71+/-0.99) and high risk of ventricular fibrillation (VF) signals (9.38+/-2.22). It is the first real-time algorithm that reports the best performance to distinguish AF and VF with sensitivity of 97.9% and specificity of 98.4%. With self-normalization, the algorithm is not subjected to the inter-variability or sampling size effects. Its computational scheme only requires matrices addition and subtraction, and thus significantly reduces the complexity for real-time implementation. It will be able to adopt in different scenarios of tele-healthcare and implantable applications. |
5,642 | Antiarrhythmic use from 1991 to 2007: insights from the Canadian Registry of Atrial Fibrillation (CARAF I and II). | The pharmacologic management of atrial fibrillation (AF), the most common sustained cardiac arrhythmia, has been traditionally dichotomized into control of ventricular rate or re-establishment and maintenance of sinus rhythm.</AbstractText>The purpose of this study was to evaluate the use of rate-controlling drugs and antiarrhythmic drugs (AAD) in the Canadian Registry of Atrial Fibrillation (CARAF) over a 16-year period from 1991 through 2007.</AbstractText>1,400 patients with new-onset paroxysmal AF who were enrolled in CARAF were included in this analysis. We assessed trends in ventricular rate-controlling medication use (digoxin, beta-blockers, and calcium channel blockers) and AAD (class IA, IC, and III antiarrhythmic agents) at baseline and follow-up visits as well as by calendar year.</AbstractText>AAD use increased initially from 1991 to 1994 (peak use 42.5%) before steadily declining. Sotalol use decreased (27% to 6%), whereas amiodarone use increased (1.6% to 17.9%). Rate-controlling medication use decreased from 1991 to 1995 (54.1% to 34.1%) due to declining digoxin use (62.9% to 16.3%). After 1999, there was a continued increase in rate-controlling medication use (peak use 52.5% in 2007) due to increased beta-blocker use (17% to 45.7%). Calcium channel blockers use changed little over the duration of the study.</AbstractText>The management of AF has undergone significant shifts since 1990, reflecting the influence of drug development, prevailing belief systems, the impact of large clinical trials, and evidence-based recommendations. Monitoring of pharmacotherapy trends will provide insight into the real-world application of evidence-based guidelines as well as allow the opportunity to identify deficiencies and improve patient care.</AbstractText>Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,643 | Multiple embolisations in rheumatic heart disease: a case report. | Though systemic thromboembolism is not an infrequent complication of rheumatic valvular disease, multiple embolic phenomena are rare.</AbstractText>To present a patient with rheumatic heart disease associated with multiple embolic complications.</AbstractText>A 44-year-old lady with rheumatic valvular disease and atrial fibrillation defaulted anticoagulant medication, and subsequently presented with acute chest pain, acute left ventricular failure, focal neurological deficit and gangrenous lower limb extremities. Electrocardiography showed atrial fibrillation and an old anteroseptal myocardial infarction. Echocardiography showed multiple valvular lesions and multiple thrombi in the left atrium. Computed tomogram scan demonstrated a large infarct involving the region supplied by the right middle cerebral artery. Bilateral above knee amputation was performed. Recovery from neurological deficit was complete. She had, during a 4-year follow-up and anticoagulation remained free of new clinically evident embolic complications. Serial echocardiography however showed that the atrial clots had persisted and presumably fibrosed.</AbstractText>Multiple systemic thromboembolisms are serious complication of atrial fibrillation of valvular aetiology, and their prevention requires continuous anticoagulation.</AbstractText> |
5,644 | Early atropine is safer than conventional atropine administration in the elderly undergoing dobutamine stress echocardiography. | Early injection of atropine during dobutamine stress echocardiography has been demonstrated in retrospective analyses to reduce the duration and dose of dobutamine infusion, while preserving a similar diagnostic accuracy with a lower incidence of adverse effects.</AbstractText>In our prospective study, we sought to explore the safety of the early atropine-dobutamine stress echocardiography protocol compared to the conventional protocol in elderly patients.</AbstractText>We enrolled 100 consecutive elderly patients who had been referred to our echocardiography laboratory for evaluation of myocardial ischemia. Once eligible, patients were randomly assigned to undergo either the conventional protocol (Group 1, 50 patients) or early atropine protocol (Group 2, 50 patients) where atropine was started at dobutamine infusion rate of 20 microg/kg/min if the heart rate was < 100 beats/min, and at 30 microg/kg/min if the heart rate was < 120 beats/min, (max 2.0 mg). Test duration and total dobutamine dose were calculated.</AbstractText>The mean age of the whole study cohort was 69.8 +/- 2.8 years, 54 (54%) being males. Patients in Group 1 received a higher total dose of dobutamine (15.7 +/- 0.8 vs 12.2 +/- 1.5 mg) and had a longer test duration (14.3 +/- 3.5 vs 11.5 +/- 1.3 min) as compared to Group 2 (p < 0.01 for both). The two groups received a similar total dose of atropine (NS). Group 1 patients had a higher incidence of ventricular extra-systoles, non-sustained ventricular tachycardia, atrial fibrillation, and hypotension.</AbstractText>In elderly patients undergoing dobutamine stress echocardiography, adopting the early atropine protocol offers a shorter test duration and a lower dobutamine dose, with consequently fewer adverse effects.</AbstractText> |
5,645 | Safety baseballs and chest protectors: a systematic review on the prevention of commotio cordis. | To determine whether chest protectors and/or safety baseballs reduce the incidence of commotio cordis during sport through a review of the best available evidence.</AbstractText>PubMed, Ovid Medline, and Embase databases from 1950 to 2009. We selected articles according to "death, sudden, cardiac," "commotio cordis," "sports equipment," and "protective devices." We identified 17 articles in the systematic literature search. Of these, 7 articles met inclusion criteria. Three independent reviewers reviewed the articles. The study results and generated conclusions were extracted and agreed on.</AbstractText>The softest safety baseball shows statistically significant reductions in the incidence of ventricular fibrillation (VF) at all velocities compared with standard baseballs in the 3 studies that evaluated their use. Different degrees of softness did not show statistically significant reductions in VF. In the 3 studies that evaluated the use of chest protectors against controls, there was an increase in protection against fatal arrhythmias; however, this was only statistically significant for 1 chest protector.</AbstractText>This systematic review shows strong supportive evidence toward a decreased rate of commotio cordis with safety baseballs when compared with standard balls. Based on the results of our systematic review, the rate of induction of VF was at its lowest when chest protection was used.</AbstractText> |
5,646 | Relationship of functional mitral regurgitation to new-onset atrial fibrillation in acute myocardial infarction. | <AbstractText Label="BACKGROUND/OBJECTIVE" NlmCategory="OBJECTIVE">The role of factors that increase left atrial pressure or cause acute left atrial dilatation is frequently emphasised in the pathogenesis of atrial fibrillation (AF) in patients with acute myocardial infarction (AMI). This study was designed to test the hypothesis that functional mitral regurgitation (FMR) occurring after AMI may promote AF by producing left atrial volume overload.</AbstractText>Intensive care unit of a tertiary care hospital.</AbstractText>1920 patients admitted with AMI were studied. Patients with known AF were excluded. FMR was classified using echocardiography into three groups: none; mild FMR and moderate or severe FMR. The relationship between FMR and AF occurring at any time during the hospital course was examined using multivariable logistic regression.</AbstractText>Mild FMR was present in 744 patients (38.8%) and moderate or severe FMR was present in 150 patients (7.8%). AF developed in 51 (5.0%), 83 (11.2%) and 28 (18.7%) patients with no FMR, mild FMR and moderate or severe FMR, respectively (p trend <0.001). In multivariable logistic regression, both mild (odds ratio (OR) 1.6; 95% CI 1.1 to 2.3, p=0.02) and moderate or severe FMR (OR 2.1; 95% CI 1.2 to 3.6, p=0.007) were independent predictors of AF. There was a significant interaction between the left ventricular ejection fraction and FMR (p=0.003) such that mild FMR was predictive of AF only in patients with a reduced (<45%) ejection fraction.</AbstractText>There is a graded independent association between the severity of FMR and the new onset of AF in patients with AMI.</AbstractText> |
5,647 | Ouabain attenuates cardiotoxicity induced by other cardiac steroids. | All cardiac steroids have a similar structure, bind to and inhibit the ubiquitous transmembrane protein Na(+), K(+)-ATPase and increase the force of contraction of heart muscle. However, there are diverse biological responses to different cardiac steroids both at the cellular and at the molecular level. Moreover, we have recently shown that ouabain inhibits digoxin- and bufalin-induced changes in membrane traffic. The present study was designed to test the hypothesis that ouabain also has an inhibitory effect on cardiotoxicity induced by other cardiac steroids.</AbstractText>The hypothesis was tested in isolated heart muscle preparations and in an in vivo model of cardiotoxicity in guinea pigs.</AbstractText>Ouabain at a low dose attenuated the toxicity induced by bufalin and digoxin in heart muscle preparations. In addition, ouabain at the low dose (91 ng.kg(-1).h(-1)), but not at a higher dose (182 ng.kg(-1).h(-1)), delayed the development of digoxin-induced (500 microg.kg(-1).h(-1)) cardiotoxicity in anaesthetized guinea pigs, as manifested by delayed arrhythmia and terminal ventricular fibrillation, as well as a reduced heart rate. In addition, as observed with ouabain, the phosphoinositide 3-kinase inhibitor wortmannin (100 microg.kg(-1).h(-1)) delayed the digoxin-induced arrhythmia in anaesthetized guinea pigs.</AbstractText>The present study demonstrates the inhibitory effect, probably through signal transduction pathways, of ouabain on digoxin- and bufalin-induced cardiotoxicity in guinea pigs. Further understanding of this phenomenon could be beneficial for increasing the therapeutic window for cardiac steroids in the treatment of chronic heart failure.</AbstractText> |
5,648 | [Hundred years of atrial fibrillation: current knowledge and perspectives]. | Atrial fibrillation (AF) is the most common sustained arrhythmia in general population. AF in humans was first described in 1903. Gradually, it has been well appreciated that AF is notjust an acceptable alternative for normal rhythm but rather a serious threat, related to increased mortality and cardiovascular morbidity. AF can precipitate or worsen pre-existing heart failure, may cause the development of tachycardiomyopathy and is an independent risk factor for thromboembolic events, most frequently stroke. It has long been believed that rhythm control is the best therapy for AF. Nowadays there is a clear scientific proof that rhythm control offers no benefit over frequency control, at least for older patients, even with advanced left ventricular dysfunction. However, optimal treatment for younger, highly symptomatic, otherwise healthy AF patients has not been designed. Available antiarrhythmics have considerable proarrhythmic potential or organ toxicity, and new safer drugs are under investigation. Nonpharmacological approaches, namely RF-catheter ablation, are rapidly developing. Prevention of thromboembolism is imperative, and new safer oral anticoagulants have been intensively investigated. Recent randomized studies (PIAF, RACE, STAF, AFFIRM, HOT-CAFE) did not solve the issue of optimal arrhythmia treatment, but they emphasized the prevention of thromboembolism based on risk factors, and not on AF type, mainly because asymptomatic episodes of AF may not be clinically recognised. |
5,649 | Implementing the 2005 American Heart Association Guidelines improves outcomes after out-of-hospital cardiac arrest. | The purpose of the study was to determine whether applying highly recommended changes in the 2005 American Heart Association (AHA) Guidelines would improve outcomes after out-of-hospital cardiac arrest.</AbstractText>In 2005, AHA recommended multiple ways to improve circulation during cardiopulmonary resuscitation (CPR).</AbstractText>Conglomerate quality assurance data were analyzed during prospective implementation of the 2005 AHA Guidelines in five emergency medical services (EMS) systems. All EMS personnel were trained in the key new aspects of the 2005 AHA Guidelines, including use of an impedance threshold device. The primary outcome was survival to hospital discharge. Secondary outcomes were return of spontaneous circulation (ROSC), survival by initial cardiac arrest rhythm, and the cerebral performance category (CPC) score at hospital discharge.</AbstractText>There were 1,605 patients in the intervention group and 1,641 patients in the control group. Demographics, the rate of bystander CPR, and time from the 911 call for help to arrival of EMS personnel were similar between groups. Survival to hospital discharge was 10.1% in the control group versus 13.1% in the intervention group (P = .007). For patients with a presenting rhythm of ventricular fibrillation/ventricular tachycardia, survival to discharge was 20% in controls versus 32.3% in the intervention group (P <.001). Survival to discharge with a CPC classification of 1 or 2 was 33.3% (10/30) in the control versus 59.6% (31/52) in the intervention group (P = .038).</AbstractText>Compared with controls, patients with out-of-hospital cardiac arrest treated with a renewed emphasis on improved circulation during CPR had significantly higher neurologically intact hospital discharge rates.</AbstractText>Copyright © 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,650 | Dronedarone: an emerging therapy for atrial fibrillation. | Atrial fibrillation (AF) is a common arrhythmia, with a prevalence ranging from 0.1% to 9.0% at different ages, and is associated with increased cardiovascular events and mortality. A significant increase in the prevalence of the disease is expected to occur in the coming years as a consequence of the aging of the population and advances in the management of coronary artery disease and heart failure. Effective rhythm control may be difficult to obtain in a significant proportion of patients with AF. The limited efficacy and the possible adverse effects of antiarrhythmic drugs has led researchers to focus their attention on new molecules, in a search of compounds with antiarrhythmic efficacy and a more favourable safety profile. Among several new drugs developed for the management of AF, dronedarone, a benzofuran derivative that shares many of the antiarrhythmic properties of amiodarone, but with a more favourable safety profile, seems particularly promising. The drug is noniodinated, has less lipophilicity, reaches therapeutic concentrations over a shorter period of time and has lower tissue accumulation. Dronedarone, similarly to amiodarone, exhibits electrophysiologic characteristics of all 4 Vaughan Williams classes. Clinical studies have shown that dronedarone effectively reduces ventricular rate, may prevent or delay the recurrence of AF, and may reduce cardiovascular morbidity and mortality in patients with AF or atrial flutter. The drug has an overall good safety profile, in particular with low pulmonary and thyroid toxicity. An important exception is represented by patients with unstable haemodynamic conditions, in which the use of dronedarone has been found to be associated with an increase in mortality. Dronedarone has been recently approved for clinical use by the Food and Drug Administration and by the European Medicines Agency. Further results from trials and clinical use will better define the efficacy and safety profile of dronedarone in AF compared with other antiarrhythmic drugs and its role in the management of patients with AF. |
5,651 | Sudden death due to isolated right ventricular infarction: a case report. | Isolated right ventricular infarction (RVI) is a rare phenomenon associated with atherosclerotic disease of the acute marginal vessels or of a non-dominant right coronary artery. It may happen in the absence of coronary disease when substantial right ventricular hypertrophy is present. The prognosis is usually good, although sudden collapse can occur due to ventricular fibrillation, rupture of the right ventricular free wall, or a massive pulmonary embolism. In this report, a case of sudden death in a patient with an isolated RVI due to an acute thrombosis of a non-dominant right coronary artery is presented.</AbstractText>A 46-year-old man without previous cardiopulmonary disease died suddenly at home. A medicolegal autopsy was performed within 72 h in order to clarify the circumstances that suddenly led the man to an unexpected death. Samples were collected for histological, immunohistochemical, and toxicological examination.</AbstractText>The postmortem investigation revealed central cyanosis, polyvisceral stasis, and pulmonary oedema. The macroscopic examination of the heart showed left and right ventricular hypertrophy. A fresh thrombus located in the right coronary artery accompanied by a haemorrhagic infiltration of the posterolateral right ventricular wall was found. Microscopic findings confirmed the observations from the autopsy and showed miliary necrosis of the right ventricular wall. Toxicology was negative for drugs and alcohol.</AbstractText>On the basis of morphologic and microscopic data, the cause of death was determined to be an isolated RVI. The autopsy findings of both right and left ventricular hypertrophy associated with a nondominant right coronary artery thrombosis were observed. In cases like this, the authors would like to underline the importance of a complete postmortem examination and a full pathological approach.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,652 | Circadian variation of human ventricular fibrillation dominant frequency. | Circadian variation in human ventricular fibrillation (VF) dominant frequency is unknown. If present this would provide evidence of physiological influence on VF. The objective was to quantify the circadian variation in human VF dominant frequency.</AbstractText>Eight-lead Holter ECG recordings were obtained from a patient with severe myocarditis and chronic VF who was supported by a biventricular assist device. Recordings of up to 24h duration were obtained on 6 days with an average interval between recordings of 7 days. Dominant frequency and amplitude were obtained using spectral analysis and assessed for (i) circadian (ii) inter-recording and (iii) inter-lead differences.</AbstractText>There was a significant circadian variation in amplitude (night: 0.027+/-0.004mVHz vs day: 0.044+/-0.006mVHz, p<0.0001) but not dominant frequency (night: 7.85+/-0.62Hz vs day: 7.93+/-0.54Hz, p>0.05). There were significant differences between recordings in dominant frequency which ranged from 6.80+/-0.29Hz to 8.36+/-0.38Hz (p<0.0001) and dominant frequency spectral amplitude which ranged from 0.033+/-0.014mVHz to 0.043+/-0.017mVHz (p<0.0001). Histograms of dominant frequencies in leads exhibited strikingly different distributions, particularly in V2 that was characterised by a bimodal distribution, while the other leads were characterised by predominantly unimodal distributions.</AbstractText>VF dominant frequency spectral amplitude exhibited circadian variability. In a patient with severe myocarditis, supported with a biventricular assist device and in chronic VF, these results provide evidence for modulation of VF, probably induced by changes in posture and physical activity.</AbstractText>Copyright 2010 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
5,653 | The spatial QRS-T angle in the Frank vectorcardiogram: accuracy of estimates derived from the 12-lead electrocardiogram. | The spatial QRS-T angle (SA), a predictor of sudden cardiac death, is a vectorcardiographic variable. Gold standard vertorcardiograms (VCGs) are recorded by using the Frank electrode positions. However, with the commonly available 12-lead ECG, VCGs must be synthesized by matrix multiplication (inverse Dower matrix/Kors matrix). Alternatively, Rautaharju proposed a method to calculate SA directly from the 12-lead ECG. Neither spatial angles computed by using the inverse Dower matrix (SA-D) nor by using the Kors matrix (SA-K) or by using Rautaharju's method (SA-R) have been validated with regard to the spatial angles as directly measured in the Frank VCG (SA-F). Our present study aimed to perform this essential validation.</AbstractText>We analyzed SAs in 1220 simultaneously recorded 12-lead ECGs and VCGs, in all data, in SA-F-based tertiles, and after stratification according to pathology or sex.</AbstractText>Linear regression of SA-K, SA-D, and SA-R on SA-F yielded offsets of 0.01 degree, 20.3 degrees, and 28.3 degrees and slopes of 0.96, 0.86, and 0.79, respectively. The bias of SA-K with respect to SA-F (mean +/- SD, -3.2 degrees +/- 13.9 degrees) was significantly (P < .001) smaller than the bias of both SA-D and SA-R with respect to SA-F (8.0 degrees +/- 18.6 degrees and 9.8 degrees +/- 24.6 degrees, respectively); tertile analysis showed a much more homogeneous behavior of the bias in SA-K than of both the bias in SA-D and in SA-R. In pathologic ECGs, there was no significant bias in SA-K; bias in men and women did not differ.</AbstractText>SA-K resembled SA-F best. In general, when there is no specific reason either to synthesize VCGs with the inverse Dower matrix or to calculate the spatial QRS-T angle with Rautaharju's method, it seems prudent to use the Kors matrix.</AbstractText>Copyright 2010 Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,654 | Nifekalant hydrochloride terminated electrical storms after coronary surgery. | An "electrical storm" is a life-threatening condition defined as a recurrent attack of ventricular tachycardia or fibrillation. The current report is a case study of a patient who had electrical storms developing unexpectedly after undergoing coronary artery bypass grafting. The electrical storms were terminated dramatically by the administration of nifekalant hydrochloride. We suggest that nifekalant hydrochloride has great therapeutic potential for the suppression of intractable ventricular tachyarrhythmias refractory to amiodarone. |
5,655 | A high-fidelity simulation mannequin to introduce pharmacy students to advanced cardiovascular life support. | To design and implement an advanced cardiac life support (ACLS) workshop featuring a human patient simulator (HPS) for third-year pharmacy students.</AbstractText>The ACLS workshop consisted of a pre-session lecture, a calculation exercise, and a 40-minute ACLS session using an HPS. Twenty-four 5-member teams of students were assigned roles on a code team and participated in a ventricular fibrillation/pulseless ventricular tachycardia case.</AbstractText>Students completed an anonymous postactivity survey instrument and knowledge quiz. Most students who completed the ACLS workshop agreed they would like to participate in additional simulation activities and that the HPS experience enhanced their understanding of ACLS and the pharmacist responsibilities during an ACLS event (99.2% and 98.3%, respectively). However, the median score on the knowledge-based questions was 25%.</AbstractText>Pharmacy students agreed HPS enhanced their learning experience; however, their retention of the knowledge learned was not consistent with the perceived benefits of HPS to education.</AbstractText> |
5,656 | Combined heart failure device diagnostics identify patients at higher risk of subsequent heart failure hospitalizations: results from PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) study. | We sought to determine the utility of combined heart failure (HF) device diagnostic information to predict clinical deterioration of HF in patients with systolic left ventricular dysfunction.</AbstractText>Some implantable devices continuously monitor HF device diagnostic information, but data are limited on the ability of combined HF device diagnostics to predict HF events.</AbstractText>The PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) was a prospective, multicenter observational study in patients receiving cardiac resynchronization therapy (CRT) implantable cardioverter-defibrillators. HF events were independently adjudicated. A combined HF device diagnostic algorithm was developed on an independent dataset. The algorithm was considered positive if a patient had 2 of the following abnormal criteria during a 1-month period: long atrial fibrillation duration, rapid ventricular rate during atrial fibrillation, high (> or =60) fluid index, low patient activity, abnormal autonomics (high night heart rate or low heart rate variability), or notable device therapy (low CRT pacing or implantable cardioverter-defibrillator shocks), or if they only had a very high (> or =100) fluid index. We used univariate and multivariable analyses to determine predictors of subsequent HF events within a month.</AbstractText>We analyzed data from 694 CRT defibrillator patients who were followed for 11.7 +/- 2 months. Ninety patients had 141 adjudicated HF hospitalizations with pulmonary congestion at least 60 days after implantation. Patients with a positive combined HF device diagnostics had a 5.5-fold increased risk of HF hospitalization with pulmonary signs or symptoms within the next month (hazard ratio: 5.5, 95% confidence interval: 3.4 to 8.8, p < 0.0001), and the risk remained high after adjusting for clinical variables (hazard ratio: 4.8, 95% confidence interval: 2.9 to 8.1, p < 0.0001).</AbstractText>Monthly review of HF device diagnostic data identifies patients at a higher risk of HF hospitalizations within the subsequent month. (PARTNERS HF: Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure; NCT00279955).</AbstractText>Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
5,657 | Successful resuscitation after prolonged periods of cardiac arrest: a new field in cardiac surgery. | Cardiopulmonary resuscitation is associated with high mortality and poor neurological recovery. Cardiopulmonary resuscitation can cause ischemia-reperfusion injury of the whole body and brain. We assessed the hypothesis that controlled reperfusion of the whole body with cardiopulmonary bypass would limit reperfusion injury after 15 minutes of normothermic cardiac arrest with better survival and neurological recovery.</AbstractText>Eleven pigs were exposed to normothermic ischemia for 15 minutes by inducing ventricular fibrillation, followed by cardiopulmonary resuscitation (control group, n = 4) or 60 minutes of cardiopulmonary bypass (treatment group, n = 7). Conditions of reperfusion and the reperfusate were controlled with cardiopulmonary bypass. Animals were observed for up to 7 days, and neurological assessment (Neurological Deficit Score: 0, normal; 500, brain death), magnetic resonance imaging, and brain histology were performed.</AbstractText>All animals in the control group died after 20 minutes of cardiopulmonary resuscitation (n = 4). All (n = 7) survived in the treatment group. Clinically apparent neurological recovery occurred within 24 hours; 1 fully conscious pig could not walk. The Neurological Deficit Score was 98 +/- 31 in all animals (n = 7) after 24 hours and decreased to 0 after 48 hours in 4 of 5 eligible animals; 1 animal had a Neurological Deficit Score of 110 after 3 days. Brain histology revealed hypoxic and apoptotic neurons with an inconclusive correlation regarding neurological recovery.</AbstractText>Clinically apparent neurological recovery after a period of 15 minutes of cardiac arrest occurred with cardiopulmonary bypass instead of cardiopulmonary resuscitation for reperfusing the whole body. This approach contrasts with cardiopulmonary resuscitation, in which resuscitation has been reported as successful after only 3 to 5 minutes of cardiac arrest. Cardiopulmonary bypass might be a key to improve survival and neurological recovery after cardiac arrest.</AbstractText>2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
5,658 | Does the E/e' index predict the maintenance of sinus rhythm after catheter ablation of atrial fibrillation? | The role of left ventricular (LV) diastolic dysfunction in recurrent atrial fibrillation (AF) after catheter ablation remains unknown. We investigated LV diastolic function using the ratio of early transmitral flow velocity (E) to early diastolic mitral annular velocity (e') and evaluated its predictive value for AF recurrence.</AbstractText>One hundred three AF patients underwent transthoracic echocardiography before ablation and during 3 months of follow-up. Clinical and echocardiographic parameters of patients with maintained sinus rhythm were compared with those with recurrent AF.</AbstractText>Of 103 patients, 26 had recurrent AF during follow-up. The E/e' index was the best independent predictor of AF recurrence in a multivariate logistic regression model. A cutoff value of 11.2 for the E/e' measured before ablation was associated with a sensitivity of 80.8% and specificity of 81.8% (area under ROC curve, 0.840; 95% CI, 0.754-0.926) for AF recurrence. E/e' measured in sinus rhythm after ablation had an even better predictive power (area under ROC curve, 0.917; 95% CI, 0.850-0.983).</AbstractText>LV diastolic function was closely associated with AF recurrence after catheter ablation. The E/e' index can be used as an incremental predictor for AF recurrence after catheter ablation.</AbstractText> |
5,659 | Severe obstructive sleep apnea elicits concentric left ventricular geometry. | Obstructive sleep apnea (OSA) has several negative effects on the heart including increase in myocardial end-systolic stress, venous return and sympathetic activity, all potential stimuli of left ventricular (LV) hypertrophy. The impact of the severity of OSA on LV geometry is unknown. We hypothesized that OSA is related to concentric LV geometry.</AbstractText>One hundred and fifty-seven patients with suspected OSA underwent echocardiography, ambulatory 24-h blood pressure and ECG monitoring. On the basis of the severity of OSA, patients were divided into controls, mild OSA and moderate/severe OSA (apnea-hypopnea index <5, 5-15 and >15/h, respectively). Patients with LV hypertrophy were defined as LV mass at least 49.2 g/m2.7 for men and at least 46.7 for women. Relative wall thickness of at least 0.43 identified patients with concentric LV geometry.</AbstractText>Patients with moderate/severe OSA (n = 86) had a higher body mass index and a higher prevalence of paroxysmal atrial fibrillation than those (n = 51) with mild OSA and controls (n = 20). Prevalence of hypertension, diabetes, obesity, LV mass and blood pressure did not differ between the groups. Relative wall thickness was positively related to apnea-hypopnea index (r = 0.30; P = 0.003) and the prevalence of concentric LV geometry was 20% in controls, 12% in mild OSA and 58% in moderate/severe OSA (P < 0.001). In logistic regression analysis concentric LV geometry was associated with moderate/severe OSA [odds ratio (OR) 7.6, P < 0.001], low stress-corrected midwall shortening (OR 3.38, P = 0.004), and higher body mass index (OR 1.09, P = 0.03).</AbstractText>Moderate/severe OSA is associated with high prevalence of concentric LV geometry. This increased prevalence may in part explain the increased rate of cardiovascular events in these patients.</AbstractText> |
5,660 | ECG spectral and morphological parameters reviewed and updated to detect adult and paediatric life-threatening arrhythmia. | Since the International Liaison Committee on Resuscitation approved the use of automated external defibrillators (AEDs) in children, efforts have been made to adapt AED algorithms designed for adult patients to detect paediatric ventricular arrhythmias accurately. In this study, we assess the performance of two spectral (A(2) and VFleak) and two morphological parameters (TCI and CM) for the detection of lethal ventricular arrhythmias using an American Heart Association (AHA) compliant database that includes adult and paediatric arrhythmias. Our objective was to evaluate how those parameters can be optimally adjusted to discriminate shockable from nonshockable rhythms in adult and paediatric patients. A total of 1473 records were analysed: 751 from 387 paediatric patients (<or=16 years of age) and 722 records from 381 adult patients. The spectral parameters showed no significant differences (p > 0.01) between the adult and paediatric patients for the shockable records; the differences for nonshockable records however were significant. Still, these parameters maintained the discrimination power when paediatric rhythms were included. A single threshold could be adjusted to obtain sensitivities and specificities above the AHA goals for the complete database. The sensitivities for ventricular fibrillation (VF) and ventricular tachycardia (VT) were 91.1% and 96.6% for VFleak, and 90.3% and 99.3% for A(2). The specificities for normal sinus rhythm (NSR) and other nonshockable rhythms were 99.5% and 96.3% for VFleak, and 99.0% and 97.7% for A(2). On the other hand, the morphological parameters showed significant differences between the adult and paediatric patients, particularly for the nonshockable records, because of the faster heart rates of the paediatric rhythms. Their performance clearly degraded with paediatric rhythms. Using a single threshold, the sensitivities and specificities were below the AHA goals, particularly VT sensitivity (60.4% for TCI and 65.8% for CM) and the specificity for other nonshockable rhythms (51.7% for TCI and 34.5% for CM). The specificities, particularly for the adult case, improve when the thresholds are independently adjusted for each adult and paediatric database. |
5,661 | Rationale and design of the NAGOYA HEART Study: comparison between valsartan and amlodipine regarding morbidity and mortality in patients with hypertension and glucose intolerance. | Inhibitors of the renin angiotensin system are recommended as the first-line medications for diabetic hypertensive patients. However, there is less evidence supporting this recommendation especially among East Asians, a population with a unique distribution of cardiovascular disease compared to the Western population.</AbstractText>The NAGOYA HEART Study is a prospective randomized open-label blinded-endpoint study to compare an angiotensin II receptor blocker, valsartan, and a calcium channel blocker, amlodipine, regarding their efficacies on cardiovascular morbidity and mortality in Japanese hypertensive patients with glucose intolerance. Of 1168 eligible patients, we enrolled 1150 patients from October 2004 to January 2009. The participants will be followed for more than a median follow-up period of 3 years. The primary composite endpoint includes myocardial infarction, stroke, coronary revascularization, and admission due to congestive heart failure or sudden cardiac death. Any of these events are adjudicated by an independent committee under blinded information regarding the treatment arm. Secondary endpoints include all-cause mortality, changes in glucose tolerance status, kidney function, left ventricular structure measured by echocardiogram, and incident atrial fibrillation/flutter. The study was registered at ClinicalTrials.gov NCT00129233.</AbstractText>The NAGOYA HEART Study will provide us with a relevant insight for appropriate treatment of hypertension with glucose intolerance.</AbstractText>Copyright 2010 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
5,662 | Effects of electric stimulations applied during absolute refractory period on cardiac function of rabbits with heart failure. | The effects of electric currents applied during absolute refractory period (ARP) on the cardiac function of rabbits with heart failure due to myocardial infarction (MI), and the safety of this method were investigated. Thirty rabbits were randomly assigned equally to 3 groups: sham-operated group, LV-anterior wall cardiac contractility modulation (LV-CCM) group, and septum-CCM (S-CCM) group. A thoracotomy was performed on all the rabbits. Electric pulses were delivered during the ARP on the anterior wall of left ventricle in CCM group and in the septum in S-CCM group, respectively. The left ventricular systolic pressure (LVSP) and maximum positive left ventricular pressure change (+dp/dt(max)), heart rates, ventricular tachycardia, ventricular fibrillation were observed. It was found that, as compared with the baseline, LVSP, and +dp/dtmax were significantly increased, on average, by 15.2% and 19.5% in LV-CCM group (P<0.05), and by 8.5% and 10.8% in S-CCM group (P<0.05). LVEDP was significantly decreased and -dp/dt(max) increased both in LV-CCM group and S-CCM group (P<0.05). CCM had no effect on heart rate and induced no arrhythmia in short time. It is concluded that electric currents delivered during the ARP could significantly enhance the contractility of myocardium safely, suggesting that CCM stimulation is a novel potent method for contractility modulation. |
5,663 | Applications of control theory to the dynamics and propagation of cardiac action potentials. | Sudden cardiac arrest is a widespread cause of death in the industrialized world. Most cases of sudden cardiac arrest are due to ventricular fibrillation (VF), a lethal cardiac arrhythmia. Electrophysiological abnormalities such as alternans (a beat-to-beat alternation in action potential duration) and conduction block have been suspected to contribute to the onset of VF. This study focuses on the use of control-systems techniques to analyze and design methods for suppressing these precursor factors. Control-systems tools, specifically controllability analysis and Lyapunov stability methods, were applied to a two-variable Karma model of the action-potential (AP) dynamics of a single cell, to analyze the effectiveness of strategies for suppressing AP abnormalities. State-feedback-integral (SFI) control was then applied to a Purkinje fiber simulated with the Karma model, where only one stimulating electrode was used to affect the system. SFI control converted both discordant alternans and 2:1 conduction block back toward more normal patterns, over a wider range of fiber lengths and pacing intervals compared with a Pyragas-type chaos controller. The advantages conferred by using feedback from multiple locations in the fiber, and using integral (i.e., memory) terms in the controller, are discussed. |
5,664 | The case for hypoglycaemia as a proarrhythmic event: basic and clinical evidence. | Recent clinical studies show that hypoglycaemia is associated with increased risk of death, especially in patients with coronary artery disease or acute myocardial infarction. This paper reviews data from cellular and clinical research supporting the hypothesis that acute hypoglycaemia increases the risk of malignant ventricular arrhythmias and death in patients with diabetes by generating the two classic abnormalities responsible for the proarrhythmic effect of medications, i.e. QT prolongation and Ca(2+) overload. Acute hypoglycaemia causes QT prolongation and the risk of ventricular tachycardia by directly suppressing K(+) currents activated during repolarisation, a proarrhythmic effect of many medications. Since diabetes itself, myocardial infarction, hypertrophy, autonomic neuropathy and congestive heart failure also cause QT prolongation, the arrhythmogenic effect of hypoglycaemia is likely to be greatest in patients with pre-existent cardiac disease and diabetes. Furthermore, the catecholamine surge during hypoglycaemia raises intracellular Ca(2+), thereby increasing the risk of ventricular tachycardia and fibrillation by the same mechanism as that activated by sympathomimetic inotropic agents and digoxin. Diabetes itself may sensitise myocardium to the arrhythmogenic effect of Ca(2+) overload. In humans, noradrenaline (norepinephrine) also lengthens action potential duration and causes further QT prolongation. Finally, both hypoglycaemia and the catecholamine response acutely lower serum K(+), which leads to QT prolongation and Ca(2+) loading. Thus, hypoglycaemia and the subsequent catecholamine surge provoke multiple, interactive, synergistic responses that are known to be proarrhythmic when associated with medications and other electrolyte abnormalities. Patients with diabetes and pre-existing cardiac disease may therefore have increased risk of ventricular tachycardia and fibrillation during hypoglycaemic episodes. |
5,665 | Atrial fibrillation management strategies and early mortality after myocardial infarction: results from the Valsartan in Acute Myocardial Infarction (VALIANT) Trial. | The management of patients with atrial fibrillation (AF) following a myocardial infarction (MI) remains uncertain. This study compared a rate control strategy to an anti-arrhythmic-based rhythm control strategy for the treatment of AF following myocardial infarction.</AbstractText><AbstractText Label="DESIGN, SETTING AND PATIENTS" NlmCategory="METHODS">We studied 1131 patients with AF after MI who were enrolled in the Valsartan in Acute Myocardial Infarction Trial (VALIANT). We classified patients into those treated with a rhythm control strategy (n=371) and those treated with a rate control strategy (n=760).</AbstractText>Using Cox models, we compared the two groups with respect to both death and stroke during two different time periods after randomisation for which data collection had been pre-specified: 0-45 days and 45-1096 days.</AbstractText>After adjustment, a rhythm control strategy was found to be associated with increased early mortality (0-45 days: HR: 1.9, 95% CI 1.2 to 3.0, p=0.004) but not late mortality (45-1096 days: HR 1.1, 95% CI 0.9 to 1.4, p=0.45). No difference was observed in the incidence of stroke (0-45 days: HR 1.2, 95% CI 0.4 to 3.7, p=0.73; 45-1096 days: HR 0.6, 95% CI 0.3 to 1.3, p=0.21).</AbstractText>In patients with AF after an MI, an anti-arrhythmic drug-based rhythm control strategy is associated with excess 45-day mortality compared with a rate control strategy, but is not associated with increased mortality outside of the immediate peri-infarct period. These results potentially identify a patient population in whom the use of anti-arrhythmic drug therapy may portend an increased risk of death.</AbstractText> |
5,666 | Risk factors for appropriate cardioverter-defibrillator shocks, inappropriate cardioverter-defibrillator shocks, and time to mortality in 549 patients with heart failure. | We investigated the risk factors for appropriate and inappropriate implantable cardioverter-defibrillator (ICD) shocks and mortality in 549 patients (mean age 74 years) with heart failure and ICDs. During a mean follow-up of 1,243 + or - 655 days, of the 549 patients, 163 (30%) had appropriate ICD shocks, 71 (13%) had inappropriate ICD shocks, and 63 (12%) died. Stepwise logistic regression analysis showed that significant independent prognostic factors for appropriate ICD shocks were smoking (odds ratio 3.7) and statins (odds ratio 0.54). The significant independent prognostic factors for inappropriate ICD shocks were atrial fibrillation (odds ratio 6.2) and statins (odds ratio 0.52). Finally, those for the interval to mortality were age (hazard ratio 1.08/1-year increase), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (hazard ratio 0.25), atrial fibrillation (hazard ratio 4.1), right ventricular pacing (hazard ratio 3.6), digoxin (hazard ratio 2.9), hypertension (hazard ratio 5.3), and statins (hazard ratio 0.32). In conclusion, in patients with heart failure and ICDs, smoking increased and statins reduced appropriate ICD shocks, atrial fibrillation increased and statins reduced inappropriate ICD shocks, and the interval to mortality was increased by age, atrial fibrillation, right ventricular pacing, hypertension, and digoxin and reduced by angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and statins. |
5,667 | Mild therapeutic hypothermia alters neuron specific enolase as an outcome predictor after resuscitation: 97 prospective hypothermia patients compared to 133 historical non-hypothermia patients. | Neuron specific enolase (NSE) has been proven effective in predicting neurological outcome after cardiac arrest with a current cut off recommendation of 33 microg/l. However, most of the corresponding studies were conducted before the introduction of mild therapeutic hypothermia (MTH). Therefore we conducted a study investigating the association between NSE and neurological outcome in patients treated with MTH.</AbstractText>In this prospective observational cohort study the data of patients after cardiac arrest receiving MTH (n = 97) were consecutively collected and compared with a retrospective non-hypothermia (NH) group (n = 133). Serum NSE was measured 72 hours after admission to ICU. Neurological outcome was classified according to the Pittsburgh cerebral performance category (CPC 1 to 5) at ICU discharge.</AbstractText>NSE serum levels were significantly lower under MTH compared to NH in univariate analysis. However, in a linear regression model NSE was affected significantly by time to return of spontaneous circulation (ROSC) and ventricular fibrillation rhythm but not by MTH. The model for neurological outcome identified NSE, NSE*MTH (interaction) as well as time to ROSC as significant predictors. Receiver Operating Characteristic (ROC) analysis revealed a higher cutoff value for unfavourable outcome (CPC 3 to 5) with a specificity of 100% in the hypothermia group (78.9 microg/l) compared to the NH group (26.9 microg/l).</AbstractText>Recommended cutoff levels for NSE 72 hours after ROSC do not reliably predict poor neurological outcome in cardiac arrest patients treated with MTH. Prospective multicentre trials are required to re-evaluate NSE cutoff values for the prediction of neurological outcome in patients treated with MTH.</AbstractText> |
5,668 | Impact of Subxiphoid Video Pericardioscopy with a Rigid Shaft on Cardiac Hemodynamics in a Porcine Model. | OBJECTIVE: Single-port subxiphoid videopericardioscopy with a rigid shaft is useful for left atrial exclusion, left ventricular pacing lead implantation, and epicardial mapping, but it may interfere with the cardiac rhythm and adversely alter hemodynamics. We examined the impact of this technique on hemodynamic indices in a porcine model. METHODS: The videopericardioscopy device was introduced into the pericardial space of 5 pigs (35-45 kg) via a subxiphoid approach and navigated to 6 anatomical targets (right atrial appendage, superior vena cava, ascending aorta, left atrial appendage (anterior and posterior approaches), transverse sinus, and atrioventricular groove). After successful target acquisition, the device was withdrawn through the subxiphoid port. When the hemodynamics stabilized, the device was navigated to another target. The heart rate, arterial blood pressure, central venous pressure, pulmonary arterial pressure, and mixed venous oxygen saturation were measured at every pre-target (subxiphoid incision) and target point. After the navigation trials, the animals were sacrificed and the mediastinum space was examined for procedure-related injuries. RESULTS: The device afforded a good view, and the navigation trials were successfully performed on the beating heart. Four animals tolerated the procedures, while 1 died of device-induced ventricular fibrillation after the trials. Hemodynamics were severely compromised at all anatomical targets except the left atrial appendage (anterior approach). CONCLUSIONS: Subxiphoid videopericardioscopy significantly interferes with the cardiac rhythm, causing life-threatening arrhythmia and hemodynamic compromise, when the target is located deep and far from the pericardiotomy. A flexible or highly articulated device would enable intrapericardial navigation without hemodynamic compromise. |
5,669 | Isolation of pulmonary vein and superior vena cava for paroxysmal atrial fibrillation in a young adult with left ventricular non-compaction. | We report a 19-year-old male patient with left ventricular non-compaction who presented with atrial fibrillation (AF) and ventricular tachycardia. Ventricular tachycardia was induced by AF with rapid ventricular response, but was prevented by electrical isolation of the pulmonary veins and superior vena cava. |
5,670 | Atrial asynchrony and function before and after electrical cardioversion for persistent atrial fibrillation. | The relation between left atrial (LA) electrical and mechanical activity is a challenging field of investigation. The availability of echocardiographic strain analysis techniques has enhanced our ability to non-invasively assess LA wall mechanical synchrony and performance. The aim of our study was to investigate how new strain analysis tools describe the improvement in LA mechanical function after sinus rhythm (SR) restoration as a result of electrical cardioversion (CV) and how such improvement mirrors endocrine profile changes.</AbstractText>Seventy-three patients, with persistent atrial fibrillation (AF) who underwent successful electrical CV, were prospectively studied with transthoracic echocardiography 1 week before CV and 1 month after SR. Speckle-tracking 2D-strain evaluation and asynchrony quantification were performed according to the standard deviation of time-to-peak (TP-SD) of deformation of six segments automatically located along the perimeter of the LA cavity, as imaged in an apical four-chamber view. We also calculated classic echocardiograhic parameters such as mitral regurgitation (MR) jet area, LA volume, LV diastolic and systolic volumes, as well as E-wave velocity and deceleration time (DT) on transmitral pulsed wave Doppler. Specimens for plasmatic brain natriuretic peptide (BNP) were also obtained before and 1 month after CV. After 1 month of SR, we detected a significant reduction in TP-SD (from 17.5 +/- 7.4 to 15.2 +/- 7.5%, P = 0.022), this being the expression of improved LA asynchrony, together with a marked increase in LA deformation (peak strain from 11.4 +/- 5.2 to 17.2 +/- 7.5%, P < 0.001) and a reduction in LA volume (-4.5 +/- 36%, P = 0.012). BNP decreased by one-third (from 127 +/- 96 to 86 +/- 89 pg/mL, P = 0.01). We also noticed improved ventricular pump performance [LV ejection fraction (EF) from 53 +/- 10 to 57 +/- 8%, P = <0.001] due to a 20 +/- 42% (P < 0.001) increase in LV diastolic volume (without variations in LV systolic volume and mass), a better diastolic profile (DT 34 +/- 64%, P = 0.003), and a reduction in MR jet area (-1.0 +/- 2.0 cm(2), P < 0.001). These findings are compatible with reverse LA remodelling secondary to SR maintenance, with a favourable effect on LV function that appears modulated by the atrium itself. A significant correlation (r = 0.40, P < 0.001) was demonstrated between TP-SD and peak strain data pre-post CV. At multivariate analysis, a significant capacity for the TP-SD/peak strain ratio to predict AF recurrence at 1-year follow-up (P = 0.013) was shown.</AbstractText>Our novel noninvasive approach appears to be able to describe the LA mechanical behaviour during AF and how this ameliorates after 1 month of SR, together with an improved endocrine profile. LA mechanical data pre-CV can predict AF recurrence 1-year post CV.</AbstractText> |
5,671 | Electromechanical wavebreak in a model of the human left ventricle. | In the present report, we introduce an integrative three-dimensional electromechanical model of the left ventricle of the human heart. Electrical activity is represented by the ionic TP06 model for human cardiac cells, and mechanical activity is represented by the Niederer-Hunter-Smith active contractile tension model and the exponential Guccione passive elasticity model. These models were embedded into an anatomic model of the left ventricle that contains a detailed description of cardiac geometry and the fiber orientation field. We demonstrated that fiber shortening and wall thickening during normal excitation were qualitatively similar to experimental recordings. We used this model to study the effect of mechanoelectrical feedback via stretch-activated channels on the stability of reentrant wave excitation. We found that mechanoelectrical feedback can induce the deterioration of an otherwise stable spiral wave into turbulent wave patterns similar to that of ventricular fibrillation. We identified the mechanisms of this transition and studied the three-dimensional organization of this mechanically induced ventricular fibrillation. |
5,672 | Minimizing pre- and post-defibrillation pauses increases the likelihood of return of spontaneous circulation (ROSC). | The three-phase model of ventricular fibrillation (VF) arrest suggests a period of compressions to "prime" the heart prior to defibrillation attempts. In addition, post-shock compressions may increase the likelihood of return of spontaneous circulation (ROSC). The optimal intervals for shock delivery following cessation of compressions (pre-shock interval) and resumption of compressions following a shock (post-shock interval) remain unclear.</AbstractText>To define optimal pre- and post-defibrillation compression pauses for out-of-hospital cardiac arrest (OOHCA).</AbstractText>All patients suffering OOHCA from VF were identified over a 1-month period. Defibrillator data were abstracted and analyzed using the combination of ECG, impedance, and audio recording. Receiver-operator curve (ROC) analysis was used to define the optimal pre- and post-shock compression intervals. Multiple logistic regression analysis was used to quantify the relationship between these intervals and ROSC. Covariates included cumulative number of defibrillation attempts, intubation status, and administration of epinephrine in the immediate pre-shock compression cycle. Cluster adjustment was performed due to the possibility of multiple defibrillation attempts for each patient.</AbstractText>A total of 36 patients with 96 defibrillation attempts were included. The ROC analysis identified an optimal pre-shock interval of <3s and an optimal post-shock interval of <6s. Increased likelihood of ROSC was observed with a pre-shock interval <3s (adjusted OR 6.7, 95% CI 2.0-22.3, p=0.002) and a post-shock interval of <6s (adjusted OR 10.7, 95% CI 2.8-41.4, p=0.001). Likelihood of ROSC was substantially increased with the optimization of both pre- and post-shock intervals (adjusted OR 13.1, 95% CI 3.4-49.9, p<0.001).</AbstractText>Decreasing pre- and post-shock compression intervals increases the likelihood of ROSC in OOHCA from VF.</AbstractText> |
5,673 | [Safety analyses from 439 patients underwent endomyocardial biopsy via the right internal jugular vein approach]. | Primary indications for endomyocardial biopsy (EMB) include heart transplant rejection surveillance and identifying cardiomyopathy or myocarditis. EMB procedures have not yet gained widespread acceptance because of concerns about possible complications associated with EMB procedures. In this single-center retrospective study, we analyzed the incidence of major and minor EMB procedure-related complications of 439 EMBs during the past 4.5 years.</AbstractText>From May 2004 to November 2008, 15 patients with cardiomyopathy and 1 patient with suspected cardiac tumor underwent 16 EMB procedures and 131 heart transplant recipients underwent 423 EMB procedures with the use of a modified Cordis bioptome. All EMB procedures were made via the right internal jugular vein approach and RV septum EMBs were performed under fluoroscopic guidance without additional echocardiographic monitoring. Operators were allowed to perform EMB procedure alone if a minimum of 50 EMB procedures had been previously supervised by a senior operator and all EMBs were performed by 4 operators. All patients underwent a 12-lead electrocardiogram (ECG), 12-hour continuous ambulatory ECG monitoring, chest X-ray and transthoracic echocardiography before and after EMB procedures to obtain a detailed evaluation of the incidence of conduction abnormalities, arrhythmias, pericardial effusions and worsening valve insufficiency.</AbstractText>There was no major complications like cardiac tamponade, hemothorax and pneumothorax. Minor complications such as conduction abnormalities including temporary RBBB (lasting < 24 h after EMB procedures) were found in 2 cases (0.47%) and sustained RBBB (> 24 h) was evidenced in 1 case (0.23%). There were no A-V block, complex ventricular arrhythmias or episodes of atrial fibrillation during and post procedure. In addition, 4 cases (0.91%)of EMB induced mild-moderate tricuspid regurgitation during the procedure were diagnosed by echocardiography.</AbstractText>The EMB procedure via the right internal jugular vein approach under fluoroscopic guidance is safe and associated with a very low complication rate when performed by experienced operators.</AbstractText> |
5,674 | [Association between metabolic syndrome and incidence of atrial fibrillation in essential hypertensive patients without left ventricular hypertrophy]. | To investigate the association between metabolic syndrome (MS) and the incidence of atrial fibrillation (AF) in essential hypertensive (EH) patients without left ventricular hypertrophy.</AbstractText>A total of 972 EH without left ventricular hypertrophy were divided into EH + non MS group (n = 606) and EH + MS group (n = 366). Incidence of AF were compared between two groups.</AbstractText>(1) Incidence of AF in EH + MS group was significantly higher than that in EH + non MS group (12.84% vs. 6.93%, P < 0.01). (2) Left atrial diameter (LAD), left ventricular end-diastolic diameter (LVEDd), interventricular septum thickness (IVS), left ventricular posterior wall thickness (LVPW) and left ventricular mass (LVM) were all significantly higher in EH + MS group than those in EH + non MS group (all P < 0.01) while left ventricular mass index (LVMI) and ejection fraction (EF) were similar between two groups. (3) Logistic regression analysis showed age, hypertension duration, LAD, LVEDd and MS were significantly correlated with incidence of AF in EH patients (OR: 1.683, 1.308, 2.262, 3.848 and 1.853, P < 0.05) and obesity was the independent predictor for incidence of AF (OR: 1.706, P = 0.029).</AbstractText>MS was associated with increased incidence of AF in EH patients without left ventricular hypertrophy in this cohort.</AbstractText> |
5,675 | Favourable outcome after 26 minutes of "Compression only" resuscitation: a case report. | A 49 year old man had ventricular fibrillation in his home, at room temperature, due to an ST-elevation myocardial infarction. He received Cardiac compression only resuscitation (CC-only) for 26 minutes by his wife, followed by four minutes of standard CPR by other lay persons until EMS-arrival. Gasping and moaning were observed during most of the CC-only period. The ambulance arrived at 30 minutes. The first ECG showed a fine ventricular fibrillation. Restoration of spontaneous circulation (ROSC) was achieved at 49 minutes after a total of four defibrillatory shocks. The patient recovered without any cerebral damage, and was discharged to his home after eight days hospitalization.</AbstractText>This case demonstrates that early and powerful cardiac compressions alone without rescue breaths may maintain sufficient circulation and gas exchange to prevent neurological damage for more than 25 minutes. This should be kept in mind for Emergency Medical Dispatch Centrals giving Pre-arrival instructions to bystanders.</AbstractText> |
5,676 | Impact of dronedarone in atrial fibrillation and flutter on stroke reduction. | Dronedarone has been developed for treatment of atrial fibrillation (AF) or atrial flutter (AFL). It is an amiodarone analogue but noniodinized and without the same adverse effects as amiodarone.</AbstractText>This is a review of 7 studies (DAFNE, ADONIS, EURIDIS, ATHENA, ANDROMEDA, ERATO and DIONYSOS) on dronedarone focusing on efficacy, safety and prevention of stroke. There was a dose-finding study (DAFNE), 3 studies focusing on maintenance of sinus rhythm (ADONIS, EURIDIS and DIONYSOS), 1 study focusing on rate control (ERATO) and 2 studies investigating mortality and morbidity (ANDROMEDA and ATHENA).</AbstractText>The target dose for dronedarone was established in the DAFNE study to be 400 mg twice daily. Both EURIDIS and ADONIS studies demonstrated that dronedarone was superior to placebo for maintaining sinus rhythm. However, DIONYSOS found that dronedarone is less efficient at maintaining sinus rhythm than amiodarone. ERATO concluded that dronedarone reduces ventricular rate in patients with chronic AF. The ANDROMEDA study in patients with severe heart failure was discontinued because of increased mortality in dronedarone group. Dronedarone reduced cardiovascular hospitalizations and mortality in patients with AF or AFL in the ATHENA trial. Secondly, according to a post hoc analysis a significant reduction in stroke was observed (annual rate 1.2% on dronedarone vs 1.8% on placebo, respectively [hazard ratio 0.66, confidence interval 0.46 to 0.96, P = 0.027]). In total, 54 cases of stroke occurred in 3439 patients (crude rate 1.6%) receiving dronedarone compared to 76 strokes in 3048 patients on placebo (crude rate 2.5%), respectively.</AbstractText>Dronedarone can be used for maintenance of sinus rhythm and can reduce stroke in patients with AF who receive usual care, which includes antithrombotic therapy and heart rate control.</AbstractText> |
5,677 | First experience of percutaneous radio-frequency ablation for atrial flutter and atrial fibrillation in a patient with HeartMate II left ventricular assist device. | We report the first case of percutaneous radio-frequency (RF) ablation procedure in a patient implanted with a HeartMate II left ventricular assist device for refractory heart failure. This procedure was performed for poorly tolerated recurrent atrial arrhythmias. No harmful consequence happened during or after the procedure despite the potential electromagnetic interferences existing between the RF delivery and the functioning of the device. |
5,678 | QRS duration and echocardiographic evidence of left ventricular dyssynchrony in patients with left ventricular systolic dysfunction. | To determine the association between left ventricular (LV) dyssynchrony assessed by tissue Doppler imaging (TDI) in patients with left ventricular ejection fraction (LVEF) < 35% and prolonged ventricular depolarization on electrocardiography.</AbstractText>A cross-sectional study.</AbstractText>The Aga Khan University, Karachi, from June to September 2007.</AbstractText>All patients with LVEF < 35% were included. Apical 2-D images were obtained in 4 chamber and 2 chamber views. TDI pulse wave Doppler parameters were measured from these 2 color-coded images. Time interval between the onset of QRS complex and the peak systolic velocity per region was derived. Patients with valvular heart disease, mitral annular calcification, atrial fibrillation and paced rhythm were excluded. Fischer's exact test was used to determine the association between QRS duration and left ventricular dyssynchrony.</AbstractText>A total of 60 patients were included. Twenty one patients had QRS duration of > 120 msec. Out of those 21 patients, a total of 6 patients (28.6%) had evidence of dyssynchrony on TDI. Five patients (23.8%) had dyssynchrony on the basis of basal septal and basal lateral velocity difference (p=0.045) and 6 patients (28.6%) had evidence of dyssynchrony based on basal anterior and basal inferior velocity difference (p=0.018). Out of the remaining 39 patients with narrow QRS complex, only 2 patients (5.1%) had dyssynchrony on TDI.</AbstractText>The study demonstrates a significant association between prolonged QRS duration and left ventricular dyssynchrony on TDI. Therefore, such patients should be screened for prolonged QRS duration on ECG before cardiac resynchronization therapy (CRT).</AbstractText> |
5,679 | Cardiac conduction disturbances and differential effects on atrial and ventricular electrophysiological properties in desmin deficient mice. | Desmin mutations in humans cause desmin-related cardiomyopathy, resulting in heart failure, atrial and ventricular arrhythmias, and sudden cardiac death. The intermediate filament desmin is strongly expressed in striated muscle cells and in Purkinje fibers of the ventricular conduction system. The aim of the present study was to characterize electrophysiological cardiac properties in a desmin-deficient mouse model.</AbstractText>The impact of desmin deficiency on cardiac electrophysiological characteristics was examined in the present study. In vivo electrophysiological studies were carried out in 29 adult desmin deficient (Des-/-) and 19 wild-type (Des+/+) mice. Additionally, epicardial activation mapping was performed in Langendorff-perfused hearts.</AbstractText>Intracardiac electrograms showed no significant differences in AV, AH, and HV intervals. Functional testing revealed equal AV-nodal refractory periods, sinus-node recovery times, and Wenckebach points. However, compared to the wild-type situation, Des-/- mice were found to have a significantly reduced atrial (23.6+/-10.3 ms vs. 31.8+/-12.5 ms; p=0.045), but prolonged ventricular refractory period (33.0+/-8.7 ms vs. 26.7+/-6.5 ms; p=0.009). The probability of induction of atrial fibrillation was significantly higher in Des-/- mice (Des-/-: 38% vs. Des+/+: 27%; p=0.0255), while ventricular tachycardias significantly were reduced (Des-/-: 7% vs. Des+/+: 21%; p<0.0001). Epicardial activation mapping showed slowing of conduction in the ventricles of Des-/- mice.</AbstractText>Des-/- mice exhibit reduced atrial but prolonged ventricular refractory periods and ventricular conduction slowing, accompanied by enhanced inducibility of atrial fibrillation and diminished susceptibility to ventricular arrhythmias. Desmin deficiency does not result in electrophysiological changes present in human desminopathies, suggesting that functional alterations rather than loss of desmin cause the cardiac alterations in these patients.</AbstractText> |
5,680 | Predictors of ventricular tachyarrhythmia in high-risk myocardial infarction patients treated with primary coronary intervention. | Background. We investigated the association between clinical characteristics, angiographic data and ventricular arrhythmia in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI)Methods. In patients with STEMI (n=225), a Holter analysis was performed the first 12 hours after primary PCI.Results. A total of 151 (66%) patients had >/=1 episode of ventricular tachycardia (VT). Age <70 years (RR 4.9, 95% CI 1.8 to 12.7), TIMI 0-1 pre-PCI (RR 2.6, 95% CI 1.1 to 6.1) and peak CK (RR 3.5, 95% CI 1.9 to 5.8) were independent predictors of VT. One-year mortality was 7%, no association between mortality and presence of early VT was found.Conclusion. Ventricular tachycardia is common in the first 12 hours after primary PCI for STEMI. Independent predictors of VT are younger age, TIMI 0-1 flow prior to PCI and larger infarct size. The presence of early VT was not significantly associated with one-year mortality. (Neth Heart J 2010;18:122-8.). |
5,681 | Myocardial gene expression alterations in peripheral blood mononuclear cells of patients with idiopathic dilated cardiomyopathy. | To assess cardiac gene expression in peripheral blood cells of patients with idiopathic dilated cardiomyopathy (IDCM) and its relationship to echocardiographic left ventricular (LV) function.</AbstractText>A complete echocardiographic study and blood sampling were performed in 65 consecutive stable IDCM patients with LV ejection fraction (LVEF) 31.76 +/- 10.07% and chronic mild to moderate heart failure (NYHA functional class II to III) for > or =9 months. Blood samples from 19 healthy individuals were included for comparison. Transcript levels of myocardin, GATA4, alpha- and beta-myosin heavy chain (MHC), sarcoplasmic reticulum calcium ATPase 2 (SERCA2), and phospholamban were determined by quantitative real-time reverse transcription-polymerase chain reaction. Myocardin (24.88 +/- 4.93 vs. 3.98 +/- 1.12, P = 0.0048) and GATA4 (17.85 +/- 4.85 vs. 0.45 +/- 0.15, P = 0.0069 x 10(-5)) were upregulated in IDCM patients compared with controls, whereas SERCA2 (5.11 +/- 0.42 vs. 8.93 +/- 1.07, P = 0.001) was downregulated. In IDCM patients, myocardin (r = 0.279, P = 0.025), GATA4 (r = 0.314, P = 0.011), beta-MHC (r = 0.444, P=0.0002), and alpha-MHC (r = 0.272, P = 0.034) showed positive correlations, whereas SERCA2 (r = -0.264, P = 0.034) exhibited a negative correlation with LVEF. Patients with elevated LV filling pressures had lower myocardin (15.06 +/- 3.10 vs. 43.12 +/- 12.03, P = 0.048), GATA4 (8.96 +/- 2.17 vs. 34.38 +/- 12.60, P = 0.026), beta-MHC (10.59 +/- 4.05 vs. 16.43 +/- 4.91, P = 0.013), and alpha-MHC (0.27 +/- 0.08 vs. 0.79 +/- 0.20, P = 0.033) and higher SERCA2 (5.65 +/- 0.54 vs. 3.90 +/- 0.61, P = 0.037) levels. Patients with atrial fibrillation (AF) had higher SERCA2 levels compared with sinus rhythm patients (6.75 +/- 0.84 vs. 4.54 +/- 0.45, P = 0.017).</AbstractText>Our data indicate that cardiac gene expression alterations in peripheral blood cells of IDCM patients may reflect alterations in LV function, whereas the presence of AF may be associated with increased SERCA2 levels in these patients.</AbstractText> |
5,682 | Acute effects of urocortin 2 on cardiac function and propensity for arrhythmias in an animal model of hypertension-induced left ventricular hypertrophy and heart failure. | To test acute effects of the corticotropin-releasing factor-related peptide urocortin 2 (Ucn2) on left ventricular (LV) function and the propensity for ventricular arrhythmias in the isolated heart of an animal model of hypertension-induced heart failure.</AbstractText>Hearts from Dahl salt-sensitive rats with severe LV dysfunction were perfused according to Langendorff. Left ventricular developed pressure and the positive and negative derivatives of LV pressure were analysed before and after perfusion with Ucn2 (n = 15) or normal perfusion solution (control, n = 9). Intracellular calcium cycling parameters were assessed by surface fluorometry. Furthermore, monophasic action potential duration (MAPD) and ventricular fibrillation threshold (VFT) were determined, the latter by a train-of-pulses method at increasing voltage to scan the vulnerable period of repolarization. Urocortin 2 significantly affected intracellular calcium cycling and improved LV contractile function and relaxation. Compared with baseline values, Ucn2 significantly decreased MAPD at 30, 50, and 90% repolarization and significantly increased VFT compared with baseline values. No changes were observed in control experiments.</AbstractText>Administration of Ucn2 rapidly improves LV function and increases VF threshold in failing, isolated rat hearts with increased propensity for ventricular arrhythmias. These observations suggest a potential use of Ucn2 as a safe and novel agent for the treatment of acute heart failure.</AbstractText> |
5,683 | Neurologically intact survival in a porcine model of cardiac arrest: manual cardiopulmonary resuscitation vs. LifeBelt cardiopulmonary resuscitation. | To compare the LifeBelt (Deca-Medica, Inc., Columbus, OH), a novel cardiopulmonary resuscitation (CPR) device, with manual CPR on the outcome of neurologically intact survival in a porcine model of cardiac arrest.</AbstractText>Twenty-two adolescent swine were randomized by permuted block design to resuscitation using LifeBelt (n = 12) or manual CPR (n = 10). The animals were instrumented with right atrial and aortic pressure catheters while they were under general anesthesia with isoflurane and nitrous oxide. Ventricular fibrillation (VF) was induced with a bipolar pacing catheter placed in the right ventricle. After 7 minutes of untreated VF, chest compressions with either LifeBelt or manual CPR were initiated along with standard Advanced Cardiac Life Support. Survivors were assigned a neurologic score using the neurologic deficit score and the cerebral performance category (CPC) score at 24, 48, and 72 hours following resuscitation by a veterinarian blinded to treatment allocation.</AbstractText>There were no significant differences in prearrest hemodynamic parameters or in important resuscitation variables between the groups. One of 12 of the LifeBelt animals failed to achieve return of spontaneous circulation (0.08, 95% confidence interval [CI] 0.002-0.38). The remaining 11 had a neurologic deficit score of 0 and a CPC score of 1, indicating normal neurologic function. All of the manual CPR animals survived. One of 10 manual CPR survivors (0.10, 95% CI 0.003-0.45) had a neurologic deficit score of 260 and a CPC score of 3, indicating moderate disability, while the remaining animals had a neurologic deficit score of 0 and a CPC score of 1.</AbstractText>In this porcine model of cardiac arrest, we did not detect significant differences in neurologically intact survival between LifeBelt CPR and manual CPR.</AbstractText> |
5,684 | Biatrial pacing vs. intravenous amiodarone in prevention of atrial fibrillation after coronary artery bypass surgery. | This study was aimed to compare the results of post operative biatrial pacing and i.v. amiodarone in prevention of AF. In a single blind randomized clinical trial, 210 patients scheduled for elective CABG surgery were randomized either to receive overdrive biatrial pacing, i.v. amiodarone or no intervention. Incidence of AF postoperatively evaluated. Pacing was successful in 83% of patients and 80% of patients in amiodarone group could receive their drug. Twenty and one patients developed AF. Incidence of AF in pace, amiodarone and control group was 10.7, 5.3 and 17.9%, respectively (p = 0.08). Comparing incidence of AF between pacing and control group, the difference was not significant (p = 0.2), but the difference between amiodarone and control groups was significant statistically (p = 0.03). Patients who developed AF were older but their left ventricular ejection fraction was not different with patients without AF. The ICU stay was higher in patients with AF. Use of i.v. amiodarone was more effective than biatrial pacing in prevention of post operative AF and we recommend use of this drug in high risk patients. |
5,685 | [Surgical outcomes of arrhythmia surgery associated with total cavo-pulmonary connection conversion for failed Fontan]. | The occurrence of late-onset supraventricular tachyarrhythmia is one of the major factors for Fontan failure. In 1999, we initiated the arrhythmia surgery with combined total cavo-pulmonary connection (TCPC) conversion for failed Fontan patients.</AbstractText>From 1999 to 2008, a total of 7 patients (5 males) underwent arrhythmia surgery with TCPC conversion for supraventricular tachyarrhythmia causing Fontan failure. Median age at operation and duration from last Fontan operation were 20.3 year-old (14.5-38.9) and 15.6 years (9.9-26.2), respectively. Previous Fontan procedure was atrio-pulmonary connection (APC) in 4 patients, lateral tunnel in 2, and right atrial-ventricular anastomosis (Bjork procedure) in 1. Right side maze procedure was applied for intraatrial reentrant tachycardia (IART) and full maze for atrial fibrillation (Afib).</AbstractText>There ware no early death and 1 late death due to infectious endocarditis for median followup at 7.4 years (1.3-10.3). None of the patients showed recurrent or new onset IART or Afib, including the late expired case. Current New York Heart Association functional class was I in 4 patients and II in 2.</AbstractText>TCPC conversion with arrhythmic surgery was successfully performed failed Fontan patients. All patients were converted to sinus rhythm and have kept it until now.</AbstractText> |
5,686 | AZD1305 exerts atrial predominant electrophysiological actions and is effective in suppressing atrial fibrillation and preventing its reinduction in the dog. | Recent development of drugs for the treatment of atrial fibrillation (AF) has focused on atrial selective agents. We examined the atrioventricular differences in sodium channel block of the antiarrhythmic agent AZD1305 in atria and ventricles of anesthetized dogs in vivo, canine isolated arterially perfused preparations in vitro, and isolated myocytes using whole-cell patch-clamp techniques. AZD1305 did not change heart rate or blood pressure in vivo but prolonged action potential duration and increased effective refractory period, diastolic threshold of excitation, and conduction time preferentially in atria both in vitro and in vivo. AZD1305 reduced the maximum rate of rise of the action potential upstroke (V(max)) predominantly in atria (-51% +/- 10% in atria vs. -31% +/- 23% in ventricles; 3 microM; cycle length = 500 milliseconds). Fast sodium current (I(Na)) was blocked by AZD1305 to a greater degree in atrial versus ventricular myocytes (particularly tonic inhibition). In coronary-perfused right atria, AZD1305 very effectively prevented induction of persistent acetylcholine-mediated AF and, in a different set of atria, terminated persistent AF (in 5 of 5 and 7 of 8 atria, respectively). In conclusion, AZD1305 exerts atrial predominant sodium channel-blocking effects in vitro and in vivo and effectively suppresses AF. |
5,687 | Electrophysiologic characteristics and topographic distribution of focal atrial tachycardias in dogs. | Focal atrial tachycardia (FAT) is a common supraventricular tachycardia in dogs.</AbstractText>To evaluate electrophysiologic characteristics and topographic distribution of FAT.</AbstractText>Sixteen dogs with symptomatic FAT.</AbstractText>Retrospective case series. Electrophysiological studies were performed to test the inducibility of documented and no documented arrhythmias. Once induced for each dog, FAT was analyzed for electrogenic mechanism, endocardial electrogram, and location.</AbstractText>Nineteen FATs could be studied in 16 dogs, 12 were automatic, 4 nonautomatic, and 3 incessant. Two dogs had >1 focus. Mean atrial cycle length (CL) was 238.2 +/- 69.2 (SD) milliseconds, mean ventricular CL of 292.7 +/- 72.5 (SD) milliseconds, with atrioventricular block in 6 cases. Mean presystolic atrial activity recorded at the ectopic focus was -39.9 +/- 17.7 (SD) milliseconds. Atrial potentials were fragmented in 11 dogs and were low amplitude in 6 dogs. Sixty-three percent of ectopic foci were distributed within the right atrium (5 crista terminalis, 3 triangle of Koch, 2 tricuspid valve annulus, 1 interatrial septum, and 1 right auricle) and 37% in the pulmonary veins (PVs) (4 right superior PV, 2 left superior PV, and 1 right inferior PV). Persistent atrial fibrillation (AF) and paroxysmal AF were triggered by FATs in 7 dogs (2 with multiple ectopic foci and 4 with at least one PV focus).</AbstractText>According to our findings, dogs have a predominance of right-sided FAT. The majority of FATs are automatic and can trigger AF, particularly in the case of PV location.</AbstractText> |
5,688 | Too long or too short? New insights into abnormal cardiac repolarization in people with chronic epilepsy and its potential role in sudden unexpected death. | Sudden unexpected death in epilepsy (SUDEP) is probably caused by periictal cardiorespiratory alterations such as central apnea, bradyarrhythmia, and neurogenic pulmonary edema. These alterations may occur in people with epilepsy and vary in duration and severity. Seizure-related ventricular tachyarrhythmias have also been hypothesized to be involved in SUDEP, but compelling evidence of these, or of predisposition to these, is lacking. Ventricular tachyarrhythmias are facilitated by pathologic cardiac repolarization. Electrocardiography (ECG) indicators of pathologic cardiac repolarization, such as prolongation or shortening of QT intervals as well as increased QT dispersion, are established risk factors for life-threatening tachyarrhythmia and sudden cardiac death (SDC). Abnormalities in cardiac repolarization have recently been described in people with epilepsy. Importantly, periictal ventricular tachycardia and fibrillation have also been reported in the absence of any underlying cardiac disease. Therefore, pathologic cardiac repolarization could promote SCD in people with epilepsy and could be one plausible cause for SUDEP. Herein, we review abnormal cardiac repolarization in people with epilepsy, describe the putative contribution of antiepileptic drugs, and discuss the potential role of pathologic cardiac repolarization in SUDEP. Based on these, measures to reduce the risk of or prevent SUDEP may include antiarrhythmic medication and implantation of cardiac combined pacemaker-defibrillator devices. |
5,689 | Concealed automaticity from an island of atrial myocardium post cavotricuspid ablation. | We report the case of a patient with paroxysmal atrial fibrillation in whom 2 previous cavotricuspid isthmus (CTI) ablations were performed for recurrent type I counterclockwise atrial flutter. One year after the last CTI ablation, the patient underwent pulmonary vein isolation for AF and reassessment of conduction block in the CTI was performed during the procedure. While mapping the CTI, activations were documented within the CTI that were dissociated from both right atrial and ventricular activity during sinus rhythm and pacing maneuvers. This dissociated activity was confined to a region delimited by the 2 previous ablation lines, the tricuspid annulus and the inferior vena cava. These findings suggest that an island of atrial myocardium with automatic activity was created within the CTI by previous ablation lines. |
5,690 | Regional variations in action potential alternans in isolated murine Scn5a (+/-) hearts during dynamic pacing. | clinical observations suggest that alternans in action potential (AP) characteristics presages breakdown of normal ordered cardiac electrical activity culminating in ventricular arrhythmogenesis. We compared such temporal nonuniformities in monophasic action potential (MAP) waveforms in left (LV) and right ventricular (RV) epicardia and endocardia of Langendorff-perfused murine wild-type (WT), and Scn5a(+/-) hearts modelling Brugada syndrome (BrS) for the first time.</AbstractText>a dynamic pacing protocol imposed successively incremented steady pacing rates between 5.5 and 33 Hz. A signal analysis algorithm detected sequences of >10 beats showing alternans. Results were compared before and following the introduction of flecainide (10 microm) and quinidine (5 microm) known to exert pro- and anti-arrhythmic effects in BrS.</AbstractText>sustained and transient amplitude and duration alternans were both frequently followed by ventricular ectopic beats and ventricular tachycardia or fibrillation. Diastolic intervals (DIs) that coincided with onsets of transient (tr) or sustained (ss) alternans in MAP duration (DI*) and amplitude (DI') were determined. Kruskal-Wallis tests followed by Bonferroni-corrected Mann-Whitney U-tests were applied to these DI results sorted by recording site, pharmacological conditions or experimental populations. WT hearts showed no significant heterogeneities in any DI. Untreated Scn5a (+/-) hearts showed earlier onsets of transient but not sustained duration alternans in LV endocardium compared with RV endocardium or LV epicardium. Flecainide administration caused earlier onsets of both transient and sustained duration alternans selectively in the RV epicardium in the Scn5a (+/-) hearts.</AbstractText>these findings in a genetic model thus implicate RV epicardial changes in the arrhythmogenicity produced by flecainide challenge in previously asymptomatic clinical BrS.</AbstractText> |
5,691 | An unexpected diagnosis: simulation reveals unanticipated deficiencies in resident physician dysrhythmia knowledge. | Decision support tools are an important adjunct to medical resuscitation. We initiated a study comparing the use of the traditional code book method versus a computerized decision support system. However, appropriate use of the tools requires correct initial recognition of the dysrhythmia. Using simulation, numerous deficiencies were revealed regarding resident physician dysrhythmia knowledge. Most importantly, the rate of incorrect dysrhythmia recognition required discontinuation of the initial study, reorganization, and implementation of a modified study to achieve the study purpose. |
5,692 | Activation becomes highly organized during long-duration ventricular fibrillation in canine hearts. | Little is known about the three-dimensional (3-D) intramural activation sequences during long-duration ventricular fibrillation (VF), including the role of the subendocardium and its Purkinje fibers (PFs) in long-duration VF maintenance. Our aim was to explore the mechanism of long-duration VF maintenance with 3-D electrical mapping. We recorded 10 min of electrically induced VF in the left ventricular anterior free wall of six 10-kg, open-chest dogs using a 3-D transmural unipolar electrode matrix (9 x 9 x 6, 2-mm spacing) that allowed us to map intramural activation sequences. At 2.5 + or - 1.8 min of VF, although the body surface ECG continued to exhibit a disorganized VF pattern, intramurally a more organized, synchronous activation pattern was first observed [locally synchronized VF (LSVF)]. This pattern occurred one or more times in all dogs and was present 33.4 + or - 31.4% of the time during 5-10 min of VF. As opposed to the preceding changing complex activation sequences of VF, during LSVF, wavefronts were large and highly repeatable near the endocardium, first exciting the endocardium almost simultaneously and then rapidly spreading toward the epicardium with different levels of conduction block en route. During LSVF, PF activations always preceded working myocardium activations near the endocardium. In conclusion, long-duration VF in dogs frequently becomes highly organized in the subendocardium, with activation fronts arising in this region and passing intramurally toward the epicardium, even though the surface ECG continues to exhibit a disorganized pattern. PFs appear to play an important role during this stage of VF. |
5,693 | Association between renin-angiotensin-aldosterone system blockers and postoperative atrial fibrillation in patients with mild and moderate left ventricular dysfunction. | The aim of the study was to evaluate the association between renin - angiotensin - aldosterone system blockers and risk of postoperative atrial fibrillation (AF) development in patients with mild and moderate left ventricular systolic dysfunction.</AbstractText>The population of this prospective and observational study consisted of 269 patients with an ejection fraction of < or = 50% undergoing coronary artery bypass and/or valve surgery. Use of renin -angiotensin-aldosterone system blockers (angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB) and spironolactone) and their association with postoperative AF (AF episode lasting < or = 5 min) were evaluated. In statistical analysis t test for independent samples, Chi-square test and Mann Whitney U test were used for comparison of variables between groups. Predictors of postoperative AF were determined by multiple logistic regression analysis.</AbstractText>During follow-up, 50 patients (13%) developed postoperative AF. With multiple logistic regression analysis, risk factors for postoperative AF were determined: left atrial diameter (OR- 1.09; 95%CI 1.01-1.16, p=0.02), age (OR-1.04; 95%CI 1.002- 1.08, p=0.04), aortic cross-clamp duration (OR- 1.03, 95%CI -1.00-1.05, p=0.01), use of left internal mammarian artery (OR-0.33; 95%CI 0.13-0.88, p=0.03), ACEIs treatment (OR-0.27; 95%CI 0.12-0.62, p=0.002), and ARBs treatment (OR - 0.21, 95%CI 0.07-0.62, p=0.005).</AbstractText>Our results indicate that although treatments with ACEIs and ARBs are associated with low incidence of postoperative AF in patients with mild and moderate left ventricular systolic dysfunction, treatment with spironolactone is not.</AbstractText> |
5,694 | [Retrospective analysis of 1650 permanent pacemaker implantations experience over two different consecutive time periods in a single cardiology clinic]. | Indications for pacing, pacing modes, and demographics of patients who underwent pacemaker implantation between two different time periods were compared in this study.</AbstractText>Pacemaker registry of our cardiology department was used to evaluate these changes from 1986 to 2007 (First period: 1986-1996, second period: 1997-2007) retrospectively.</AbstractText>Registry revealed 776 implantations in the first and 874 implantations in the second period. The percentages of first implantation were 89% and 70.1% respectively. Nearly 50% of the patients in both periods were female. Main indications for pacing were atrioventricular (AV) block, sick sinus syndrome (SSS) and slow ventricular rate during atrial fibrillation in both periods. Implantation of VVI-AAI pacemakers have decreased (77.8%/1.5% to 51%/0.3%, p=0.05) and implantation of DDD-VDD pacemakers have increased (19.3%/1.3% to 42.3%/6.3%, p=0.05) during the second period compared to the first period. Permanent pacemaker implantation for SSS has decreased significantly from 31.1% in the first period to 12.0% (p=0.05) in the second period. Implantation for AV block has increased significantly from 63.3% to 79.7% (p=0.05) in the second period.</AbstractText>Our data revealed temporal changes in pacemaker implantation practice during last twenty years in the cardiology department of a teaching hospital. Implantation of VVI-AAI pacemakers have decreased significantly during the second period. Permanent pacemaker implantation for AV block has also decreased during the last period.</AbstractText> |
5,695 | Pacemaker/implantable cardioverter-defibrillator interaction. | We describe a case of pacemaker/implantable cardioverter-defibrillator (ICD) interaction in a single system causing failure to detect induced ventricular fibrillation (VF) in an 83-year-old man with ischemic cardiomyopathy. He underwent an ICD generator replacement due to battery depletion. In addition, a right atrial lead was placed to treat symptomatic bradycardia. Appropriate sensing and pacing parameters were observed in both leads during implant, and there was no cross-talk between the leads. A defibrillation threshold (DFT) test was performed (sense 1.5 mV, shock on T) with induction of VF that was not detected by the device, ultimately requiring an external defibrillation to terminate the arrhythmia. The device printout during testing showed atrial/ventricular lead cross-talk caused by the 1.1-J shock to induce VF, sensed beats in the noise window activating the noise suppression algorithm and preventing initial VF detection, and recurrent resetting of the automatic gain control due to ventricular sensing of the atrial pacing artifact preventing detection and perpetuating atrioventricular (AV) pacing at a rate of 60 bpm. In conclusion, pacemaker/ICD interaction can occur in a dual-chamber ICD system. This can be prevented by programming a shorter AV delay, increasing sensitivity (i.e., more sensitive value), and programming a pause before initiating pacing after an ICD discharge. |
5,696 | What can be done when asymptomatic patients discover they have Brugada syndrome? A case report of Brugada syndrome. | Brugada syndrome is an inherited cardiac disorder associated with a specific electrocardiographic pattern, involving ST segment elevation in leads V1 to V3. When not spontaneously terminated, it can lead to ventricular fibrillation and sudden death. We present a case report of a young male whose brother suffered a sudden cardiac arrest while playing soccer. A novel mutation c.2678G>A was detected on the gene SCN5A through molecular diagnosis. The mutation was shown to be present in the individual, his daughter and his other brother. For patients with previous ventricular fibrillation and/or syncope, implantable cardiac device (ICD) is recommended. However, how can patients without symptoms but with a clear diagnosis prevent cardiac arrest? |
5,697 | Connexin-43 redistribution and gap junction activation during forced restraint protects against sudden arrhythmic death in rats. | Connexin-43 (Cx43) expression is reduced or redistributed in heart disease. Restraint or other emotional stressors might cause sudden death in persons with such diseases, but the mechanism of death and its connection to Cx43 during restraint remain unknown. Whether Cx43 distribution or gap junction (GJ) function during restraint is involved in sudden arrhythmic death in rats is addressed in this study.</AbstractText>Male Sprague-Dawley rats underwent immobilization (IMO), and individual electrocardiographic responses were monitored by telemetry. Heart sections were used to examine ventricular Cx43 distribution, and GJ intercellular communication (GJIC) activity was assessed using a dye-transfer assay. IMO induced the translocation of Cx43 into to the GJ-rich fraction, with a peak at 60 min. During IMO, Cx43 immunofluorescence was enhanced at intercalated discs, in association with GJIC activation, and premature ventricular contractions (PVCs) increased. In the presence of the GJ inhibitor, carbenoxolone (0.25 mg.kg(-1).h(-1)), IMO induced lethal ventricular tachycardia or fibrillation in 21.7% of rats, in association with QRS prolongation and increased PVCs.</AbstractText>IMO causes Cx43 translocation to intercalated discs, thereby reducing vulnerability to lethal arrhythmias via enhancing GJ coupling.</AbstractText> |
5,698 | Feasibility of cardiac resynchronization therapy in a patient with complex congenital heart disease and dextrocardia, facilitated by cardiac computed tomography and coronary sinus venography. | We describe a case with pacemaker implantation for cardiac resynchronization therapy (CRT) in a patient with complex congenital heart disease, facilitated by cardiac computed tomography (CT) and coronary sinus (CS) venography. A 37-year-old male presented with congenitally corrected transposition of the great arteries and mesocardia, along with a history of two open heart surgeries (closure of atrial septal defects and a ventricular septal defect, and pulmonary valvectomy at age 7; mechanical tricuspid valve replacement at age 13). He showed symptoms of progressive heart failure (NYHA class III) with significant impairment of the systemic right ventricular function. He also developed permanent atrial fibrillation with a junctional rhythm at a rate of 45 beats per minute. Biventricular pacing without an atrial lead was considered to be the best option available. CRT implantation was facilitated by proper identification of CS anatomy utilizing cardiac CT and CS venography and was performed without any complications. At follow up, a postero-anterior chest X-ray showed the final position of the right-sided ventricular (left ventricular morphology) lead pointing to the apex and the left ventricular lead at the posterolateral aspect of the systemic ventricle (right ventricular morphology). |
5,699 | Etiology and outcome of cardioembolic stroke in young adults in Greece. | Cardioembolism is the most frequent cause of ischemic stroke in Greece. However, data regarding this stroke subtype in young adults from Greece and the East Mediterranean area are scarce.</AbstractText>We aimed to determine the source of embolism and evaluate outcomes in a sample of young Greek patients with ischemic stroke of cardioembolic etiology. A series of 245 Greek patients with ischemic stroke at an age up to 45 years were selected from a consecutive series of 2820 first-ever stroke patients admitted to our departments during the period January 1998 to December 2008.</AbstractText>Cardioembolism was diagnosed in 45 cases (18.4%). Almost half of the cases (48.9%) were attributed to congenital anomalies of the interatrial septum, including 13 cases of patent foramen ovale (28.9%), 7 cases of atrial septum aneurysm (15.6%), and 1 case with both defects (2.2%). The majority of strokes in our young patient collective were related to medium-risk sources of embolism, while high-risk sources, namely dilated cardiomyopathy, atrial fibrillation and akinetic left ventricular lesions, were found in only 33.3%. The overall probability of 10-year survival was 89.4% (95% confidence interval 79.4-99.4), whereas the probability of a new composite vascular event was 14.3% (95% confidence interval 2.3-26.3) during the same period. The clinical outcome in general was excellent, since the majority of patients (82.2%) showed no significant handicap on follow up.</AbstractText>As in other western countries, it would seem that atrioseptal abnormalities played an important role as a cause of cardioembolism in this young Greek population, whereas atrial fibrillation and other major cardioembolic sources seem to be of minor relevance as compared to stroke in elderly patients.</AbstractText> |
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