Baroreflex sensitivity and the blood pressure response to β-blockade

Abstract

The objective of this analysis was to determine whether changes in baroreflex sensitivity (BRS) within 35 hypertensive patients (25 M, 10 F, mean age 47 years) treated with ␤-blockade as monotherapy relate to reductions in ambulatory blood pressure (BP) or its variability. BP was recorded intra-arterially directly from the brachial artery before and during submaximal exercise. BRS was determined by the phenylephrine injection technique. MAP and its variability were determined for the awake period of 24-h BP monitoring. Subjects were randomised to one of atenolol, metoprolol, pindolol, or propranolol, and restudied after a mean of 5 months. ␤-blockade increased BRS in 24 patients and decreased BRS in 11. BRS increased from 6.53 ؎ 4.94 to 9.40 ؎ 8.62 ms/mm Hg (mean ؎ s.d.) (P Ͻ 0.01). Waking ambulatory MAP decreased from 125.8 ؎ 15.8 to 106.4 ؎ 16.2 mm Hg (P Ͻ 0.0001), but its variability did not change. Higher BRS after chronic ␤-blockade was associated with a decrease in waking ambulatory MAP (r ‫؍‬ ؊0.55,

Nocturnal hemodialysis increases arterial baroreflex sensitivity and compliance and normalizes blood pressure of hypertensive patients with end-stage renal disease

“…Moreover, this augmentation occurred in the setting of withdrawal of angiotensin-converting enzyme (ACE) inhibitors, b adrenoceptor antagonists, and angiotensin receptor blockers. Because each of these drug classes has been shown to improve arterial baroreflex sensitivity [19,35,42,43], and ACE inhibitors have been shown to decrease pulse wave velocity (i.e., increase compliance) in hemodialysis patients [44], an even greater increase in both arterial baroreflex sensitivity and arterial compliance might have been anticipated, had these antihypertensives been continued up until the time of the nocturnal hemodialysis study.…”

Geomagnetic field effect on cardiovascular regulation

“…A considerable amount of evidence suggests that even in the absence of arterial hypertension, a high blood pressure variability, as well as, decreased BRS and HR variability, are considered as independent risk factors for greater vascular and target organ damage [Chen et al, 1999] and are associated with increased cardiovascular morbidity and mortality [Parati et al, 1996;La Rovere et al, 1998;Pickering, 1998;Stauss and Persson, 2000].…”

Autonomic impairment in tetanus: Delayed baroreflex involvement

“…This might be related to beta-blocker (metoprolol) administration with the aim to control autonomic instability which was started on day 2 and was withdrawn on day 3. Betablockers are known to positively influence baroreflex sensitivity [12,13]. In the next 2 measurements (days 4 and 5) baroreflex sensitivity was markedly decreased to the level of complete baroreflex failure.…”