Effects of Beta-Adrenergic Blockade on Short-Term Variability of Blood Pressure and Heart Rate in Essential Hypertension

Abstract

Short-term fluctuations in blood pressure (BP) and heart rate (HR) were analysed in a group of twelve males with essential hypertension. Indirect finger BP was measured by a Finapres device. The effect of a 7-day administration of a cardioselective beta-adrenoceptor blocker, acebutolol (400 mg/day), was studied in a double-blind, randomized, placebo-controlled cross-over study. Compared with placebo, acebutolol caused a significant decrease in BP and HR. In addition, the standard deviation (SD) of BP and HR were reduced after acebutolol in the standing position. Spectral analysis of fluctuations in BP showed a reduction in the variability underlying the SD changes of BP and HR. This reduction predominated in the mid frequency (MF) region corresponding to Mayer waves. This effect was marked for HR since the MF component for standing HR after acebutolol was 46% the placebo level. The average reduction in MF component for standing Systolic BP (SBP) was 36%. No significant correlation was found between the Mayer wave reduction and the systolic, diastolic BP or HR lowering effect of acebutolol. No significant changes in the gain of the transfer function between MF SBP and HR fluctuations in the standing position were observed. The reduced MF component of HR and BP variability after acebutolol could be due to a peripheral cardiac and non-cardiac sympatholytic effect of chronic beta-adrenoceptor blockade.

Intérêt de l’exploration du système nerveux autonome dans les troubles vésicosphinctériens

“…Tout test sera précédé d'un repos du patient de dix minutes. Avant le début du test, on s'assurera de l'absence de médicament pouvant interférer avec le SNA : bêtabloqueur, bêta-agoniste per os, alpha 1 bloqueur, alpha 2 agoniste (clonidine, prasozine, yohimbine) anticholinergique, antidépresseur tricyclique, cholinomimétique [8,9].…”

Neuropathie végétative diabétique: principes et méthodes d’exploration

“…Tout test sera précédé d'un repos du patient d'au moins 15 minutes. Avant le début du test, on s'assurera de l'absence de médicament pouvant interférer avec le système nerveux autonome : bêtabloqueur, bêta-agoniste per os, alpha-1-bloqueur, alpha-2-agoniste, anticholinergique, antidépresseur tricyclique, cholinomimétique [7,10].…”

A delay recruitment model of the cardiovascular control system

“…The baroreceptor response to arterial pressure is nonlinear [21], and is attenuated at very high and very low pressures. There are strong clinical links between sympathetic activity and Mayer waves -if sympathetic activity is chemically blocked, Mayer waves are significantly reduced or completely eliminated [4,15,3,8]. Indeed, Guyton and Harris [19] proposed the term vasomotor waves for blood pressure oscillations slower than respiration.…”