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Abstract Background: Sudden cardiac death is the most frequent death mechanism in Chagas disease, responsible for 55% to 65% of the deaths of patients with chronic Chagas cardiomyopathy (CCC). The most often involved electrophysiological mechanisms are ventricular tachycardia and ventricular fibrillation. The implantable cardioverter defibrillator (ICD) has a beneficial role in preventing sudden death due to malignant ventricular arrhythmias, and, thus the correct identification of patients at risk is required. The association of microvolt T-wave alternans (MTWA) with the appearance of ventricular arrhythmias has been assessed in different heart diseases. The role of MTWA is mostly unknown in patients with CCC. Objectives: To evaluate the association between MTWA and the occurrence of malignant ventricular arrhythmias in patients with CCC. Method: This is a case-control study including patients with CCC and ICD, with history of malignant ventricular arrhythmias (case group), and patients with CCC and no history of those arrhythmias (control group). The MTWA test results were classified as negative and non-negative (positive and indeterminate). The significance level adopted was a = 0.05. Results: We recruited 96 patients, 45 cases (46.8%) and 51 controls (53.1%). The MTWA test was non-negative in 36/45 cases (80%) and 15/51 controls (29.4%) [OR = 9.60 (95%CI: 3.41 - 27.93)]. After adjustment for known confounding factors in a logistic regression model, the non-negative result continued to be associated with malignant ventricular arrhythmias [OR = 5.17 (95%CI: 1.05 - 25.51)]. Conclusion: Patients with CCC and history of malignant ventricular arrhythmias more often have a non-negative MTWA test as compared to patients with no history of arrhythmia.

Sudden cardiac death in athletes is a recurrent phenomenon at sporting events and during training. Recent studies have associated sudden cardiac death with such cardiovascular conditions as coronary artery anomalies, cardiomyopathies, and electrocardiographic abnormalities, most of which are screenable with modern imaging techniques. We recently inaugurated the Center for Coronary Artery Anomalies at the Texas Heart Institute, which is dedicated to preventing sudden cardiac death in the young and investigating coronary artery anomalies. There, we are conducting 2 cross-sectional studies intended to firmly establish and quantify, in a large group of individuals from a general population, risk factors for sudden cardiac death that arise from specific cardiovascular conditions. In a pilot screening study, we are using a brief, focused clinical questionnaire, electrocardiography, and a simplified novel cardiovascular magnetic resonance screening protocol in approximately 10,000 unselected 11- to 15-year-old children. Concurrently, we are prospectively studying the prevalence of these same conditions, their severity, and their relation to exercise and mode of death in approximately 6,500 consecutive necropsy cases referred to a large forensic center. Eventually, we hope to use our findings to develop a more efficient method of preventing sudden cardiac death in athletes. We believe that these studies will help quantify sudden cardiac death risk factors and the relevance of associated physical activities--crucial information in evaluating the feasibility and affordability of cardiovascular magnetic resonance-based screening. We discuss the rationale for and methods of this long-term endeavor, in advance of reporting the results. [ABSTRACT FROM AUTHOR]