Evidence of Increased Sympathetic Vasomotor Drive with Shorter Acting Dihydropyridine Calcium Channel Antagonists in Human Hypertension: A Study Using Spectral Analysis of RR Interval and Systolic Arterial Pressure Variability

Abstract

We studied the effects of common antihypertensive regimens on autonomic cardiovascular control. We considered calcium channel antagonists (nicardipine twice a day and isradipine once a day, respectively) and also examined, as reference treatments, once-a-day atenolol and cilazapril. A noninvasive evaluation of autonomic cardiovascular profile was obtained with spectral analysis of RR interval and systolic arterial pressure variability. We studied moderate essential hypertensives before and after 2 weeks of treatment, both at rest and during active standing and mental arithmetic. All treatments reduced arterial pressure equally well; however, marked differences in spectral profiles were observed. The low-frequency spectral component of RR interval variability [in normalized units, marker of sympathetic modulation of the sinoatrial (SA) node] tended to be greater at rest and during stimuli (p