The effects of intravenous Verapamil administration on ventricular function were evaluated using grated radionuclide ventriculography in 15 patients with essential hypertension. Verapamil(0.1mg/kg) was injected as a bolus for 2 minutes followed by an infusion of 0.007mg/kg/min. Heart rate, blood pressure, ejection fraction, peak ejection rate, total filling time, and prak filling rate were assessed before and after Verapamil administration. The results were was as follows ; 1) Verapamil administration increased heart rate from 63+/-5 to 75+/-9 beats/min(p<0.01) and reduced systolic and diastolic blood pressure from 156+/-17/99+/-6mmHg to 139+/-16/88+/-6mmHg(p<0.01). 2) Ejection fraction, peak ejection rate, and total filling time were not changed significantly after Verapamil injection. 3) Right and left ventricular peak filling rate increased significantly only in patients in whom it was subnormal in the basal study) from 1.6+/-0.4 to 2.3+/-1.1 end-diastolic volumes/s, p<0.05 and from 2.5+/-0.6 to 3.1+/-0.8 end-diastolic volumes/s, p<0.05, respectively). In conclusion, it was found that intravenous Verapamil administration enhances ventricular diatolic function in patients with essential hypertension.