Sudden cardiac death.

Sudden cardiac death (SCD) due to ventricular tachyarrhythmias is a leading cause of death in the United States. This phenomenon is associated with coronary artery disease, valvular heart disease, nonischemic cardiomyopathies, congenital heart disease, primary electrical abnormalities, autonomic nervous system abnormalities, and other less common disorders. Evaluation and management of patients at risk for SCD (primary prevention) and of patients who have survived at least 1 episode of SCD (secondary prevention) have evolved in recent years because clinical trials have shown consistent benefit from implantation of cardioverter-defibrillators in appropriately selected patients. An evidence-based approach to primary and secondary prevention of SCD is presented.