EFFECT OF A CALCIUM INHIBITOR, NIFEDIPINE, ON EXERCISE TOLERANCE IN PATIENTS WITH ANGINA-PECTORIS - A DOUBLE-BLIND-STUDY
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Date
1981
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Abstract
The effect of nifedipine on exercise tolerance was studied in 30 patients with stable angina and positive graded exercise testing. Treadmill exercise testing was performed on each of 5 consecutive days. Placebo or nifedipine, 10 mg sublingually, was given 30 min before exercise on the 3rd day. The following day the intervention was reversed in a double-blind manner. Angina was abolished by nifedipine but not by placebo in 12 patients (40%). The time to onset of angina in the remaining patients increased from 4.1 .+-. 0.4 (SEM [standard error of mean]) to 6.7 .+-. 0.6 min (P < 0.001). Time to ST depression .gtoreq. 2 mm increased from 4.0 .+-. 0.3 to 5.4 .+-. 0.5 min, while duration of exercise increased from 6.3 .+-. 0.3 to 8.2 .+-. 0.4 min (P < 0.001). The maximum heart rate was 145 .+-. 3.3 with nifedipine and 122 .+-. 3.8 min-1 with placebo (P < 0.01). Resting systolic blood pressure decreased 30 min after nifedipine administration from 131 .+-. 3.4 to 106 .+-. 2.9 mm Hg (P < 0.01). Maximal systolic blood pressure during exercise was lower with nifedipine (127 .+-. 4.8 mm Hg) than with placebo (155 .+-. 8.6 mm Hg, P < 0.01). Nifedipine significantly improves the exercise tolerance of patients with stable angina pectoris by decreasing peripheral vascular resistance and myocardial O2 demand.