Comparison of the reflex heart rate response to rising and falling arterial pressure in man

Different Predictive Values of Electrophysiological Testing and Autonomic Assessment in Patients Surviving a Sustained Arrhythmic Episode

“…20 Baroreflex sensitivity in humans has mainly been assessed using pharmacological methods, administering agents that cause changes in blood pressure but do not directly affect heart rate. 21 One of these methods in particular, the one based on the use of the vasoconstrictor drug phenylephrine, has been shown to provide independent prognostic information in patients after MI. 11 Despite this important clinical evidence and the current availability of non-invasive beat-to-beat pressure monitors as an alternative to intra-arterial cannulation, the pharmacological methods still have difficulties related to the need for repeated (usually 3) bolus injections of the drug.…”

Squatting test: a dynamic postural manoeuvre to study baroreflex sensitivity

“…The sensitivity, or gain, of the arterial baroreflex is calculated routinely from the relation of tachycardie and/or bradycardic responses to decreases and/or increases in systemic arterial pressure [26,27]. The classical assessment of baroreflex gain used a pharmacological approach with the infusion of angiotensin or phenylephrine to generate a vasopressor stimulus and of nitroprusside or amyl nitrite to induce vasodilation and BP fall [28,29]. These pharmacological tools were designed to perturb the system, induce rapid and large HR responses and assess reflex gain.…”

Baroreflex Buffering of Sympathetic Activation During Sleep

“…26,27 Specifically targeted additional studies are required for a finer definition of this issue. However, within the framework of the present investigation, it could be argued that the lack of changes in BRS in response to BP decrease could indicate that arterial baroreflexes act more to defend the lower HR of sleep rather than to oppose it.…”