Abstract
Despite major advances in the understanding of cardiac pathophysiology and the development of sophisticated diagnostic and therapeutic modalities, sudden cardiac death remains a major clinical and public health problem. More than 300,000 sudden cardiac deaths occur each year in the United States, accounting for approximately 50% of all cardiovascular deaths. Prospective identification of patients at high risk for cardiac arrest is difficult. Progress measured in terms of prevention of large numbers of sudden cardiac deaths remains limited until it is possible to identify higher risk individuals within the currently less focused subgroups.