Heart failure (HF) is a common and lethal syndrome. Those with moderate left ventricular dysfunction have a substantial risk of premature and sudden death, approximately 25% over 2.5 years. Fifty percent of these deaths are thought to be sudden due to dysrhythmias, which may be preventable. As a consequence, patients with HF represent the largest, single identifiable population of patients that can be targeted for primary prevention of sudden cardiac death. A trial known as SCD-HeFT (The Sudden Cardiac Death in Heart Failure Trial), sponsored by the National Heart Lung and Blood Institute of the National Institutes of Health, was designed to evaluate the value of the prophylactic amiodarone or implantable cardioverter defibrillator therapy in patients with HF. This article reviews 4 key clinical insights highlighted by the SCD-HeFT results: (1) ramifications of implantable cardioverter defibrillator use in patients with New York Heart Association (NYHA) class II HF; (2) the value or lack thereof of implantable cardioverter defibrillator therapy in patients with NYHA class III HF; (3) the danger of amiodarone drug therapy in patients with NYHA class III HF; and (4) the significant value of basic medical management, when well implemented, in prolonging life in this population. In addition, future directions in the evaluation and management of patients with moderate to severe HF are addressed.