Objective:The purpose of this study is to compare the effects of nifedipine and benazepril on cardiac autonomic nervous activities in patients with essential hypertension. Methods:Hypertensive patients were randomly divided into two groups. One group was treated with nifedipine

the other with benazepril. Antihypertensive effects and cardiac autonomic nervous activities were measured with ambulatory blood pressure monitoring and 24-hour Holter recordings before and after two-week treatment. Results:Sixteen patients in nifedipine group and 18 in benazepril group finished the test. Mean doses of nifedipine and benazepril were 45.0mg/d and 16.6mg/d respectively. After 2 weeks

significant antihypertensive effects were comparable between 2 groups. The mean values of LF

HF

SDNN and pNN50 calculated from 24-hour Holter recordings were significantly reduced

and LF/HF was increased in nifedipine group. The changes of above parameters after benazepril treament were quite the contrary. Conclusion:At the similar antihypertensive efficacy

nifedipine decreased parasympathetic activity

however

benazepril increased parasympathetic activity.