ABSTRACT
The efficacy and duration of the effects of verapamil on angina threshold during exercise were examined in five patients with proved angina pectoris, with the experimental model of a latin square 5 X 5. The effects of verapamil (0,1 mg/kg i.v.) were compared with those of a placebo (20 ml saline i.v.), of isosorbide dinitrate (5 mg, sublingual), of propranolol (0,1 mg/kg i.v.), and of dipyridamol (20 mg i.v.). All the treatments were studied within 20 minutes after administration; the efficacy of the "drugs" was checked against placebo. Verapamil and isosorbide dinitrate significantly prolonged the duration of exercise and total amount of work done before angina and EKG alteration appearance. Similar changes were observed after propranolol, but not significantly different from the effects of placebo. Dipyridamol reduced thw work performance, without significant difference from placebo. The effects of verapamil, though less marked than its peak effects, were still present 70 minutes after administration. The possible mechanism of work performance improvements induced by verapamil in angina pectoris is briefly discussed on the basis of the Triple Product changes observed during exercise.
