The majority of deaths from coronary heart disease (CHD) occur before the victims receive medical attention. Chronic ventricular ectopic activity (VEA) is a well-established predictor of coronary mortality and sudden death. Evidence that chronic VEA is independently and causally related to sudden death remains equivocal. Only more advanced grades of chronic VEA appear to be significant. Arrhythmias are clearly more common in patients with advanced coronary obstruction, and prone to new ischemic events and their associated electrical disturbances. Autopsy studies are limited in their ability to identify an acute myocardial infarction in patients who die suddenly, but experience with the mobile coronary care units has reemphasized the role of acute ischemia. The prospective, randomized trial, including reliable assessment of VEA, offers the only definitive means of identifying the contribution of chronic VEA to the incidence of sudden death from CHD.