THIS study consists of detailed clinical observations on 100 consecutive cases of acute myocardial infarction at St. Luke's Hospital, New York City. Eighty-five of these patients were observed from one to ten years prior to the initial attack, for an average of four years, either on the wards or as outpatients. Follow-up studies of from one to four years were made on 64 of the 66 survivors.The criteria used for making the diagnosis were those enumerated by Shillito et al.1: fever, tachycardia, leukocytosis, elevated sedimentation rate and electrocardiographic and blood-pressure changes.So far as could be determined, the . . .