EFFECT OF PROPRANOLOL ON EXERCISE-INDUCED ISCHEMIC S-T SEGMENT DEPRESSION

The effects of propranolol on exercise-induced ischemic S-T segment depression were assessed in 11 patients with angina pectoris. In 9 of the 11 patients administration of propranolol increased exercise tolerance, as measured by walking on a treadmill. Maximal S-T depression was decreased by propranolol in 9 patients, and for the entire group of 11, maximal S-T depression was reduced from an average of 2.3 to 1.0 mm. In 4 patients this depression was limited to 0.2 mm. or less, and in 2 of them it was completely prevented. The amount of exercise necessary to induce S-T depression of 1 mm. was increased by propranolol in 6 of the 7 patients with this degree of depression. The average increase in the 7 patients was 72 per cent. These data suggest that propranolol, which has been shown to decrease the frequency of chest pain in angina pectoris, improves the relation between myocardial oxygen supply and demand while it increases exercise tolerance. © 1969.