[The effect of diltiazem and nifedipine on exercise-induced ST-segment depression and heart rate in patients with coronary heart disease (author's transl)].

In 10 patients with angina pectoris and angiographically proven coronary heart disease, the effect of 60 mg of orally administered diltiazem (D) and 20 mg of nifedipine (N) on heart rate and exercise-induced ST-segment depression was investigated under randomized double-blind conditions. A significant reduction in mean ST-segment depression could be observed at 90 and 180 minutes for N (-36% and -33%) and D (-28% and -27%). One patient did not improve after D; two patients showed a paradoxic increase in ST-segment depression after N. Mean heart rate at rest, during, and after exercise compared to the drug-free periods was lower for D and higher for N. The difference in mean heart rate between N and D was significant (p less than 0.001). In respect to their ability to reduce ST-segment depression, 20 mg of N appears to be nearly equipotent to 60 mg of D. The different effects of D and N on heart rate and AV condition must be considered in certain clinical settings.