Effects of nifedipine and diltiazem on myocardial ischemia in patients with severe stable angina pectoris treated with nitrates and beta-blockers.

In a randomized, cross-over, double-blind study, the effects of nifedipine were compared with those of diltiazem in 20 patients with severe stable angina pectoris and multivessel coronary artery disease treated with nitrates and beta-blockers. The comparison was performed by bicycle ergometry, clinical evaluation, and ambulatory 24-h ECG monitoring for 7-8 weeks. As compared with placebo, both nifedipine and diltiazem significantly reduced the daily number of anginal attacks and nitroglycerin consumption; prolonged exercise duration, time to 1-mm ST segment depression, and to onset of angina; and reduced the sum of ST segment depressions at maximal identical load in ergometry. In ambulatory ECG monitoring, only nifedipine significantly diminished the duration of asymptomatic ST segment depression as compared with placebo. Antianginal and antiischemic effects of nifedipine and diltiazem were similar. Both nifedipine and diltiazem significantly increased the effects of treatment with nitrates and beta-blockers. Administration of nifedipine was safer because at night diltiazem caused significant bradycardia despite careful titration of optimum doses of the drug. Although the maximum well-tolerated doses of conventional medication suppressed anginal symptoms in some patients, they did not abolish ischemia either at ergometry or in daily life.