Results from several recently completed trials have important implications for the primary prevention of Sudden Cardiac Death Prevention (Table below). In patients with coronary artery disease, prior myocardial infarction, and ejection fraction of 30% or less, a survival benefit was found with prophylactic implantation of a cardioverter defibrillator compared with medical therapy (MADIT-II). In the MADIT-II trial, benefits in patients with preexisting left bundle branch block were more pronounced. In the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), an ICD was associated with improved survival compared with amiodarone or medical therapy in patients with class II or III heart failure symptoms and an ejection fraction of 35% or less, and the benefit was evident in patients with or without ischemia (48%). (more…)