Patients were stratified by presence or absence of coronary artery disease, left ventricular function, and presence or absence of drug failure prior to randomization. All patients underwent an evaluation of left ventricular ejection fraction, usually by radionuclide ventriculography, and baseline drug-free Holter recording or electrophysiologic study, or both. A total of 113 patients were randomized to amiodarone and 115 patients to conventional therapy with other antiarrhythmic agents which included procainamide, quinidine, disopyramide, tocainide, mexiletine, encainide, flecainide, propafenone, moricizine, or combination therapy in that order. Holter exams were given at one, three, six, twelve, twenty-four, and thirty-six months. Patients were followed for one to five years, with an average of three years overall. Primary endpoints for the study included in the term 'cardiac survival' were cardiac mortality, resuscitated cardiac arrest due to documented ventricular fibrillation, and complete syncope followed by a shock from an automated implanted defibrillator. These endpoints included sudden arrhythmic cardiac death, resuscitated out-of-hospital ventricular fibrillation, and nonarrhythmic cardiac death. A patient death due to amiodarone pulmonary toxicity was also considered a primary endpoint.