Treatment with the new calcium antagonist isradipine significantly reduced diastolic blood pressure to less than 90 mm Hg in 64% of fourteen blacks with mild or moderately severe essential hypertension. There was a significant reduction in the echocardiographic measures of left ventricular wall thickness and mass in these patients. There was also an increase in fractional left ventricular mass index, shortening and ejection fraction per 100 g left ventricular mass and no indication in mean circumferential shortening. There was another indication of improved left ventricular performance. With the reduced left ventricular mass and diastolic blood pressure, there was a reduction in the ratio of peak systolic wall stress to fractional shortening per 100 g left ventricular mass. There was a significant relationship between peak systolic wall stress and fractional shortening per 100 g left ventricular mass index. The directional change after left ventricular mass reduction with isradipine indicated improved left ventricular function. There was an increase in left ventricular wall thickness and mass both in those patients not controlled on isradipine combined with those treated with placebo (n = 10), and in those treated with placebo (n = 5) there was an increase in wall thickness. These changes occurred in five weeks. There was no regression to a lower mean of left ventricular mass or wall thickness during placebo. There was reduction in electrocardiogram (ECG) ST-T changes of ischemia in those patients with diastolic blood pressure reduced to less than 90 mm Hg. Isradipine monotherapy was an effective antihypertensive drug in blacks with essential hypertension, resulting in regression of left ventricular wall thickness and mass and augmentation of fractional shortening per 100 g left ventricular mass.