Genetics of Sudden Death (Report‪)‬

Introduction Sudden death is estimated to account for nearly 450,000 deaths annually in the United States, which represents a prevalence of 0.1 per cent in the general population (1). Ventricular tachyarrhythmias (either ventricular fibrillation or ventricular tachycardia) are responsible for disordered ventricular contraction resulting in sudden death in most of the cases. Coronary artery disease (CAD) is the major underlying substrate responsible for sudden death--in fact, majority of such events are the presenting manifestation of previously quiescent CAD (2). Myocardial diseases such as dilated cardiomyopathy and hypertrophic cardiomyopathy along with primary electrical diseases of the heart such as long QT syndrome, Brugada syndrome, idiopathic ventricular fibrillation, etc. account for about 15-20 per cent of sudden deaths (2). In patients with clinically manifest coronary artery disease, clinical parameters such as reduced ventricular function, history of heart failure, frequent ventricular ectopy, inducible ventricular tachycardia on electrophysiologic studies, and abnormal autonomic function tests such as heart rate variability and abnormal microvolt T wave alternans are markers for an increased probability of sudden death (3). One of the strongest clinical predictors of occurrence of sudden death in these patients is a parental history of sudden death (4), and genes could play a direct role at least in some causes of sudden death. Many studies have documented this genetic influence on occurrence of sudden death (4-10). This article reviews the recent advances about the role of genetics in sudden death.