Effect of oral propranolol on rest, exercise and postexercise left ventricular performance in normal subjects and patients with coronary artery disease.

Abstract

The effect of .beta.-adrenergic blockade with oral propranolol on resting, exercise and postexercise ventricular performance was evaluated using multiple-gated equilibrium cardiac blood pool images in normal volunteers and patients with coronary artery disease. Propranolol produced no detectable effect on basal left ventricular function in normal subjects at doses producing intermediate (160 mg propranolol/day) and maximal (434 .+-. 99 mg propranolol/day) .beta. blockade and in patients with coronary artery disease at clinically effective antianginal doses (162 .+-. 47 mg propranolol/day). During exercise, a dose-related, negative inotropic effect was observed in normal subjects: 160 mg propranolol/day produced a small but statistically insignificant decline in exercise left ventricular performance. Maximal .beta. blockade significantly depressed the left ventricular response to exercise. In patients with coronary artery disease, propranolol''s effect on exercise ventricular performance depended on the presence or absence of ischemic dysfunction during exercise. In patients with an ischemic functional response to exercise, propranolol significantly improved regional and global performance during and after exercise. In coronary artery disease patients with a normal response to exercise, propranolol had no significant effect on exercise and postexercise ventricular function. Increased sensitivity to the effects of .beta. blockade in ischemic myocardium is suggested. In coronary artery disease patients with an abnormal response to exercise and in normal volunteers during .beta. blockade, propranolol''s effect on exercise left ventricular performance was independent of changes in ventricular preload and afterload related to heart rate and blood pressure.