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Objectives In this study of patients with Chagas heart disease (CHD) with an implantable cardioverter defibrillator (ICD) for secondary prevention of sudden cardiac death, we sought to compare the characteristics of those with or without electrical storm (ES) during long-term follow-up. Background ES is a common problem in patients with CHD harboring an ICD, but data on clinical predictors and outcomes are limited. Methods We retrospectively evaluated 110 patients with CHD with a mean follow-up of 1949 ± 1271 days. Demographic, clinical, arrhythmia characteristics, ICD treatment, and death data were collected. Descriptive statistics included mean ± SD and Fisher exact tests used for comparisons. A p-value Results The ES group (57 patients; 43 men; 62 ± 10 years) and the non-ES group (53 patients; 43 men; 57 ± 14 years) had similar baseline demographic and clinical parameters, but left ventricular ejection fraction was higher in the ES group (44% ± 14% vs. 37% ± 14%, p = 0.02) and QRS duration was shorter (109 ± 35 ms vs. 134 ± 36 ms; p = 0.0027). Mortality rates were comparable in the 2 groups (odds ratio: 1.2; 95% confidence interval: 0.79 to 1.85; p = 0.44). The ES group presented 116 ES (2.03 ±1.47, 1 to 6). A total of 2,953 (61%) arrhythmic events required ICD therapy. No deaths occurred directly caused by ES, but clinical triggers were reported in 20 patients. Conclusions ES is frequent in CHD but in itself does not carry a worse prognosis in this study population and was not associated with a more depressed left ventricular systolic function or a longer QRS.

Ventricular pre-excitation is one of the rarest causes of cardiomyopathy induced or mediated by arrhythmia. Right accessory pathways, specifically with left bundle branch block pattern, can cause ventricular dysfunction, since abnormal ventricular activation resulting from anterograde atrioventricular conduction can cause atrioventricular, interventricular, and intraventricular dyssynchrony, with asynchronous contraction of the ventricular wall and mitral regurgitation. An asymptomatic patient, with ventricular pre-excitation with left bundle branch block and moderate ventricular dysfunction at echocardiography, was described. The electrophysiological study demonstrated an accessory route of anterior location and with an anterograde refractory period of 600 ms, successfully performing radiofrequency ablation and substantial improvement of ventricular function.

BACKGROUND Chagas heart disease (CHD) is a dilated cardiomyopathy characterized by malignant ventricular arrhythmias and increased risk of sudden cardiac death (SCD). Much controversy exists concerning the efficacy of implantable cardioverter-defibrillator (ICDs) in CHD because of mixed results observed. We report our long-term experience with ICDs for secondary prevention in CHD, with the specific aim of assessing the results in groups with preserved or depressed global left ventricular function. METHODS 111 patients (75 males; 60 ± 12 years) were followed for 1,948 ± 1,275 days after ICD. Time to death was the primary outcome; LVEF ≤ 45% the exposure; and age, gender, and ICD therapy delivery the potential confounders. We used time-to-event methods and Cox proportional models for analysis, censoring observations at time of death or at 5-year follow-up in survivors. RESULTS Seventy-two percent of the patients presented at least one sustained ventricular arrhythmia requiring appropriate therapy, and only three patients received inappropriate therapy. Death occurred in 50 (45%) patients, with an annual mortality rate of 8.4%, mostly due to refractory heart failure or noncardiac causes. Unadjusted survival rates were significantly distinct between patients with left ventricular ejection fraction (LVEF) ≤ 45% (26 deaths), 50.5% (95% confidence interval [CI]: 36.2%-63.2%) when compared to patients with LVEF > 45% (10 deaths), 77.6% (95% CI: 62.3%-87.3%, P

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Aims Corticosteroids attenuate late growth of radiofrequency (RF) lesions in the thigh muscle of infant rats. We sought to assess the impact of these drugs on the late growth of RF lesions in immature swine myocardium and to determine the electroanatomical mapping (EAM) characteristics of these lesions.Methods and results Radiofrequency (60 degrees C; 60 s) lesions were created in the right atrium (n = 2) and ventricle (n = 2) of 14 piglets (age 65 days; weight 5 kg) and 3 adults. Piglets were divided into: controls (n 7) and treated (n 7), receiving hydrocortisone (10 mg/kg iv after RF) and prednisone (1 mg/kg/day) for 29 days. After 8 months, animals were sacrificed for histological analysis. in four piglets, endocardial and epicardial voltage EAM were performed.In infant groups, the dimensions of atrial (11 +/- 5 vs. 13 +/- 7 mm) and ventricular (12 +/- 3 vs. 11 +/- 3 mm) lesions were similar. in adults, atrial (6 +/- 1 mm) and ventricular (6 +/- 1 mm) lesions were smaller. in controls, ventricular lesions depicted dense fibrosis and multiple strands of fibrous tissue extending from the lesion into normal muscle. Treated piglets revealed scars exhibiting less dense fibrosis with predominance of fibroadipose tissue and less collagen proliferation. Large atrial and ventricular low-voltage areas corresponding to the macroscopic lesions were identified in all animals.Conclusion Radiofrequency lesions in infant pigs reveal late growth and invasion of normal muscle by intense collagen proliferation. Corticosteroids do not prevent late enlargement of the lesions but modulate the fibrotic proliferation. the expressive growth of the lesion may generate low-voltage areas detectable by EAM. Universidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, Brazil Universidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, Brazil Universidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, Brazil Universidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, Brazil Web of Science

Background: Electrical storm (ES) is a common problem in Chagas cardiomyopathy (CC) patients harboring an implantable cardioverter defibrillator (ICD), but data on clinical predictors and outcomes is limited. In this study of CC patients with an ICD for secondary prevention of sudden cardiac death

The evaluation of patients recovered from sudden death (SD) is based on diagnostic investigation aiming to identify structural heart diseases or exclusion of noncardiac diseases and metabolic disorders. After exclusion of these pathologies, one is faced with sudden cardiac death (SCD) without structural heart disease, in which electrical and latent heart diseases account for up to 56% of cases, while the remaining is considered idiopathic disease 1. This latter group has been gradually reduced due to the increasing characterization of molecular mechanisms that generate potentially lethal arrhythmias. We report the case of a young patient recovered from SCD, with no apparent structural heart disease, probably due to electrical heart disease associated with occult anomalous bundle and both diagnoses being possible according to the available means in clinical practice.

Background: Alcohol has been related to atrial fibrillation (holiday heart syndrome), but its electrophysiologic actions remain unclear. Methods: We evaluated the effects of alcohol in 23 anesthetized dogs at baseline and after 2 cumulative intravenous doses of ethanol: first dose 1.5 ml/kg (plasma level 200 mg/dl); second dose 1.0 ml/kg (279 mg/dl). In 13 closed-chest dogs (5 with intact autonomic nervous system, 5 under combined autonomic blockade and 3 sham controls), electrophysiologic evaluation and monophasic action potential (MAP) recordings were undertaken in the right atrium and ventricle. In 5 additional dogs, open-chest biatrial epicardial mapping with 8 bipoles on Bachmann’s bundle was undertaken. In the remaining 5 dogs, 2D echocardiograms and ultrastructural analysis were performed. Results: In closed-chest dogs with intact autonomic nervous system, ethanol had no effects on surface electrocardiogram and intracardiac variables. At a cycle length of 300 milliseconds, no effects were noted on atrial and ventricular refractoriness and on the right atrial MAP. These results were not altered by autonomic blockade. No changes occurred in sham controls. In open-chest dogs, ethanol did not affect inter-atrial conduction time, conduction velocity, and wavelength. Atrial arrhythmias were not induced in any dog, either at baseline or after ethanol. Histological and ultrastructural findings were normal but left ventricular (LV) ejection fraction decreased in treated dogs (77 vs. 73 vs. 66%; p = 0.04). Conclusion: Ethanol at medium and high doses depresses LV systolic function but has no effects on atrial electrophysiological parameters. These findings suggest that acute alcoholic intoxication does not directly promote atrial arrhythmias.

Background: Although radiofrequency (RF) ablation within the caval veins has been increasingly used to treat a variety of atrial tachyarrhythmias, the consequences of RF ablation in the caval veins are unknown. We explored the acute and chronic angiographic and pathological effects of extensive RF ablation in the caval veins. Methods: Under fluoroscopy guidance, conventional (4 mm tip, 60°C, 60 seconds) RF applications (n = 6–7) were delivered in each vena cava (from ±2 cm into the vein to the veno-atrial junction) of 15 dogs (10 ± 3 kg). Animals were killed 1 hour and 5 weeks after ablation for histological analysis. Angiography was performed before ablation (acute dogs only) and at sacrifice to assess the degree of vascular stenosis. Results: In acute dogs (n = 5), luminal narrowing was noted in 10/10 (100%) targeted veins (mild in two; moderate in three and severe in five, including two total occlusions). In the six chronic animals that completed the protocol (four died during follow-up), stenosis was also observed in 12/12 (100%) ablated veins (mild in six; moderate in four and severe in two). Of these, one superior vena cava was suboccluded with development of extensive collateral circulation. Histologically, acute lesions displayed typical transmural coagulative necrosis, whereas chronic lesions revealed intimal proliferation, necrotic muscle replaced with collagen, endovascular contraction, and disruption and thickening of the internal elastic lamina. Conclusion: In this model, extensive RF ablation in the caval veins may result in significant vascular stenosis. These findings may have implications for catheter ablation of arrhythmias originating within the caval veins.