Reflections on the use of propranolol in angina pectoris

Abstract

The effects of oral verapamil (V), 400 mg/day, oral propranolol (P), 300 mg/day, and placebo were compared in 10 patients admitted to the coronary care unit because of frequent attacks of angina at rest. Testing was done according to a randomized, double-blind, multiple-crossover, placebo-controlled trial, consisting of 8 consecutive 48-hour treatment periods with V or P or placebo. Three patients had variant angina, 5 had episodes of both ST-segment elevation and depression and 2 had only ST-segment depression. One patient had no critical coronary stenoses, 1 had 1-vessel disease, 7 had 2-vessel disease and 1 had 3-vessel disease. Electrocardiographic monitoring and tape recording were continued during the 16 days of the trial. A total of 1,602 episodes of transient diagnostic ST shift were recorded during the trial (1,309 episodes of ST-segment elevation, 293 of ST-segment depression); 43% were painless. Mean blood levels of V and P at the end of the active phases were 161 ± 89 and 120 ± 45 ng/ml, respectively. In the group as a whole, the average number of diagnostic ischemic ST-segment shifts per 24 hours was significantly reduced relative to corresponding placebo periods during V (2.6 ± 2.4 vs 11.9 ± 8.6; p < 0.01) but not during P treatment (11.9 ± 8.6 vs 12.0 ± 7.3). Similar statistically significant reductions were observed in the number of anginal attacks and nitroglycerin tablets consumed. Considering individual patients, V reduced ischemic episodes during both active phases in all patients, whereas P was effective only in 1. In particular, P was not effective in 3 patients with severe limitation of exercise tolerance, but did not increase consistently the number or duration of episodes in the 3 patients with variant angina.