Despite substantial progress in the management of ischemic heart disease and congestive heart failure, long-term mortality rates as a result of sudden cardiac death in such patients remain significant. Risk stratification that uses a combination of several predictors of clinical outcome has improved our ability to identify persons at high risk for future arrhythmic events. beta-Blockers and amiodarone are effective in primary prevention of sudden death in selected populations. In view of the impressive reduction in sudden death rates by implantable cardioverter defibrillators (ICDs) in patients with a history of cardiac arrest, prophylactic implantation may also be beneficial. The best way to treat these patients is not known. Three ongoing controlled clinical trials have been designed for drugs, ICDs, or both and will provide answers about whether prophylactic antiarrhythmic intervention with ICDs improves survival and whether device therapy is superior to pharmacologic treatment. Brief reports on these clinical trials are discussed in this review.