Improvement of myocardial metabolism in coronary arterial disease by beta-blockade.

Abstract

Twenty patients with angina pectoris associated with obstructive coronary arterial disease were investigated by stressing the heart by atrial pacing. Arterial and coronary sinus blood was sampled and the time taken to provoke angina (pacing time) measured. Nine of the patients acted as a control group and did not receive beta-blocking drugs. In this group both pacing time and myocardial lactate extraction were reproducible provided that 45 minutes rest was allowed between pacing tests: we have called this period the myocardial recovery time. The 11 remaining patients were paced before and after beta-blockade, the rate being kept constant for each patient. In contrast to the control group, beta-blockade improved myocardial metabolism