Comparative effects of prolonged therapy with four calcium ion antagonists (diltiazem, nicardipine, tiapamil and verapamil) in patients with chronic stable angina pectoris

Abstract

The comparative effects of prolonged chronic therapy with diltiazem, nicardipine, tiapamil and verapamil on exercise tolerance, ST-segment changes and heart rate were examined in 63 patients with established chronic stable angina pectoris. Multistage computer-assisted symptom-limited treadmill exercise tests were performed after 2 weeks of placebo ("baseline") and then after 4 months of open-label chronic drug therapy. Diltiazem improved the exercise duration by 95% (p less than 0.001), nicardipine by 45% (p less than 0.001), tiapamil by 69% and verapamil by 79% (p less than 0.001). Maximal ST-segment depression was not altered by any of the drugs, but time to the development of 1 mm ST-segment depression was significantly improved in all cases. Diltiazem and verapamil reduced the heart rate at rest significantly by 6 and 8 beats/minute, respectively, whereas nicardipine increased it by 10 beats/minute (p less than 0.02), and tiapamil did not produce any significant change. Maximal heart rate at the peak of exercise was increased by 14% with nicardipine (p less than 0.001) and 6% with verapamil (p less than 0.05), whereas diltiazem and tiapamil did not produce any appreciable effect. The rate-pressure product at the peak of exercise remained unaltered with diltiazem, tiapamil and verapamil, but with nicardipine it increased significantly to 222 +/- 10 units from a baseline of 175 +/- 6 units with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)