As much as half of the mortality in patients with congestive heart failure (CHF) resulting from left ventricular systolic dysfunction is attributable to sudden cardiac death. Thus, the identification of risk and prevention of sudden death are important components of treating this population of patients. Antiarrhythmic drugs have been shown to be either neutral or harmful when studied in patients with prior myocardial infarction and impaired left ventricular function. Amiodarone, when studied in patients with CHF, may be of benefit. This benefit may be more pronounced in patients with nonischemic cardiomyopathy. Implantable cardioverter defibrillators (ICDs) are of clear benefit when used in the primary and secondary prevention of sudden death in selected populations. Studies soon to be completed should clarify the role of the cardioverter-defibrillator in patients with CHF. Antiarrhythmic medications are often used in conjunction with ICDs for a variety of reasons. However, these drugs have the potential to adversely affect defibrillator function, and knowledge of these effects is important when using this strategy.