Epidemiologic studies had indicated that complex ventricular premature beats made an independent contribution to risk of sudden death in survivors of a myocardial infarction (MI), and did not appear to be merely a reflection of their association with relatively severe myocardial damage. The potential for reduction in mortality by identification and administration of drugs capable of safely suppressing ventricular arrhythmias was tremendous. In 1982, there was incomplete knowledge regarding which types of ventricular arrhythmias responded to various kinds of drugs. A pilot study of antiarrhythmic agents helped clarify this issue.