From 1972 through 1976, 288 patients were entered into this randomized clinical trial. One hundred forty-seven patients received intensive pharmacological medical therapy, and 141 comparable patients underwent coronary artery bypass surgery. Careful follow-up studies were performed on patients in both groups, in-hospital and during the post-hospital phase. These studies included, apart from routine physical examinations, resting electrocardiograms, chest x-ray films, and grade exercise tolerance tests at six months and twelve months.