A comparison of pharmacologic and spontaneous baroreflex methods in aging and hypertension

Abstract

Background-Phenylephrine bolus injection is an established technique to measure baroreflex sensitivity (BRS). This study quantified the relationship between the phenylephrine method and noninvasive measures of BRS and examined the effects of aging and hypertension on BRS. We also examined whether heart rate variability (HRV) provides as much information as does BRS.

Squatting test: a dynamic postural manoeuvre to study baroreflex sensitivity

“…Second, standardizing method for squatting has been requested, as various groups used different protocols [8,11,38]. Third, the calculation of baroreflex gain during a squatting test has not been validated in comparison to the classical pharmacological procedure in healthy volunteers [33,34], even if a significant correlation between the barosensitivity indices measured by the two methods has been recently reported in diabetic patients [38].…”

“…A noninvasive method based on BP changes during the late phases of Valsalva manoeuvre was proposed. Indeed, phase IV of the Valsalva manoeuvre is normally characterized by BP overshoot with concomitant reflex bradycardia, allowing to calculate cardiac vagal baroreflex gain [32][33][34][35].…”

Influência da idade no comportamento da frequência cardíaca na transição repouso-exercício: uma análise por deltas e regressão linear

“…On the other hand, the groups did not present difference in the ∆0-30s comparison, which indicates that the YG presents higher vagal removal intensity in the earlier phase of the rest-exercise transition (0-10s) and the MAG in the later phase (10-30s). The decrease of autonomic reflex response capacity suffers influence of aging due to alterations in the baroreflex consequent of the decrease of sensitivity of the peripheral receptors 10 . This mechanism may have led to delay in the HR observed in the earlier phase (∆0-10s) of the rest-exercise transition 23,24 in the MAG.…”

“…The HR autonomic modulation is very complex, since its behavior may be influenced by many peripheral afferent stimuli as well as by central mechanisms 7,10 . The concept of the signs derived from the upper brain centers, which influence the HR behavior during physical exercise, regardless of the type of exercise, was widely studied 22,23 and has been accepted by the scientific community.…”

“…The slow HR increase, which is due to the adrenergic sympathetic activation, is present from the 60 to 90s 4 . This standard, characterized in studies with [6][7][8] and without 9 pharmacological block, may suffer age and the level of physical conditioning influence 10 . Some mathematical approaches may help to characterize and understand the behavior of the HR responses in the rest-exercise transition.…”