Slow-release nifedipine versus placebo in the treatment of arterial hypertension. A double blind ergometric evaluation of cardiac workload.

The effects of slow-release nifedipine on blood pressure and cardiac workload have been studied during bicycle exercise testing in a randomized, double blind trial in 20 patients with mild to moderate hypertension. After a fortnight's wash-out, patients were allocated to either slow-release nifedipine (20 mg twice daily) or placebo for a 2-month period. At baseline and at the end of treatment blood pressure and heart rate were measured at rest and during ergometric exercise; cardiac workload was calculated as the product of systolic blood pressure by heart rate. Significant decreases in blood pressure at rest and in cardiac workload on exercise were demonstrated at the end of nifedipine treatment. The reduction of cardiac workload was mainly due to the lower baseline values of resting blood pressure. Heart rate showed a reduction of its increase during ergometric exercise at the end of nifedipine treatment as compared to baseline, likely due to an improvement in stroke volume.