Each year over 400,000 people in the United States die suddenly of coronary heart disease. The majority have known coronary heart disease. Of these, the post-myocardial infarction population constitutes a large proportion. About 8 to 15 percent of patients who recover from an acute myocardial infarction die in the subsequent year. Half of these deaths are usually sudden, presumably due to arrhythmia. Advanced age, poor ventricular function, and presence of ventricular arrhythmias can identify post-MI patients at high risk of sudden cardiac death and all-cause mortality.