COMPARISON OF EFFECTS OF ANTIHYPERTENSIVE DRUGS ON HEART-RATE - CHANGES FROM BASE-LINE BY BASE-LINE GROUP AND OVER TIME

Baseline heart rate is becoming recognized as a predictor of cardiovas cular risk. Various antihypertensive drugs have differing effects on h eart rate. A randomized controlled clinical trial of 1292 ambulatory m en with stage 1 or 2 hypertension was conducted in 15 Veterans Affairs medical centers. Patients were treated with hydrochlorothiazide, aten olol, captopril, clonidine, diltiazem, prazosin, or placebo for up to 2 years. Heart rates were measured at baseline, the end of titration, 1 year, and 2 years. Data were also stratified by baseline heart rate. A subset of patients had heart rate also determined by electrocardiog ram. All drugs except prazosin reduced heart rate from baseline; addit ional small decreases were obtained over time with hydrochlorothiazide and placebo. The decrease initially achieved with clonidine was atten uated over time. The overall reduction in heart rate was greatest for atenolol (-12.2 beats/min) and least for prazosin (+3.8 beats/min). On ly atenolol effected a further reduction of heart rate for patients wh ose baseline rate was less than or equal to 65 beats/min. All drugs re duced heart rate when the baseline was greater than or equal to 85 bea ts/min. Data derived by electrocardiogram yielded similar results. The drugs used in this study differ in their ability to reduce heart rate , sustain that reduction over time, and to change heart rate in groups with high or low rates at baseline. The importance of these comparati ve changes as independent cardiac risk factor variables remains to be determined. (C) 1998 American Journal of Hypertension, Ltd.