Effects of Calcium Antagonists on Blood Pressure, Heart Rate and Double Product After Isometric Exercise

The antihypertensive effect of calcium antagonists was studied in patients with mild-to-moderate uncomplicated essential hypertension after isometric exercise, following a 2-week washout and one-week placebo period the measurements of blood pressure and heart rate (HR) were made at rest and after isometric exercise. After 2-week drug treatment with nicardipine (NC) (20 mgx3 daily) in 16 patients (mean age 48±8), nitrendipine (NT) (20 mg once daily) in 20 patients (mean age 53) and verapamil slow-release formulation (VR) (240 mg once daily) in 12 patients (mean age 53±10) the same measurements were made. The initial and the maximum mean systolic (SBP) and diastolic blood pressure (DBP) during isometric exercise were not significantly different between three groups and HR was significantly higher in NC group than in VR group and DP was significantly lower in VR group after treatment. Although the means of the differences between initial and maximum, (D), SBP and DBP in three groups were not significantly different before treatment, the difference was significantly lower in VR group than the other two groups after treatment. D HR were significantly lower in NC group before treatment, but this difference disappeared after therapy. It is concluded that NC, NT and VR are similarly effective in reducing the blood pressure rise, cardiovascular response and myocardial O2 consumption during isometric exercise. But VR reduces myocardial O2 consumption more than NC and NT by decreasing both the HR and blood pressure.