This study is a prospective, double-masked, randomized, clinical trial to determine the effect of anti-arrhythmic drug therapy on mortality in patients with congestive heart failure and ventricular arrhythmia. Patients will be assigned to receive either amiodarone or placebo. Eligible patients include those with ischemic and nonischemic congestive heart failure (New York Heart Association class III or VI) and with 10 or more ventricular premature beats per hour. All patients must have shortness of breath with minimal exertion or paroxysmal nocturnal dyspnea, a left ventricular internal dimension (LVIDd) by echocardiogram of 55 mm or greater (> or = 55 mm) or a CT ratio of greater than 0.5, and an ejection fraction of 40% of less. Patients will be entered into the study for 2.5 years and followed for an additional 2 years. Drug therapy will be continued for all patients throughout the entire study unless adverse reactions occur that necessitate individualized treatment. The expectation is that 674 patients are to be entered into the study from 25 participating centers. This sample size will allow for the detection of a 33% decrease in 2-year mortality (20% vs. 30%) in the treated patients as compared to those in the placebo group with a power of 0.90 and a two-sided alpha level of 0.05. Intermittent Holter monitoring, radionuclide ventriculograms, pulmonary function tests, echocardiograms, and blood tests, including arterial blood gases, will be required for each patient. The study analysis will address differences in total mortality, cardiac mortality, and sudden cardiac death between patients receiving anti-arrhythmic drug therapy and those receiving placebo. Other factors to be examined include the effects of antiarrhythmic therapy on suppression of arrhythmias, on ejection fraction, and relation of ischemic events to mortality.