New insights into differential baroreflex control of heart rate in humans

P. J. Fadel, M. Strømstad, D. W. Wray, S. A. Smith, P. B. Raven, N. H. Secher

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Recent data indicate that bilateral carotid sinus denervation in patients results in a chronic impairment in the rapid reflex control of blood pressure during orthostasis. These findings are inconsistent with previous human experimental investigations indicating a minimal role for the carotid baroreceptor-cardiac reflex in blood pressure control. Therefore, we reexamined arterial baroreflex [carotid (CBR) and aortic baroreflex (ABR)] control of heart rate (HR) using newly developed methodologies. In 10 healthy men, 27 ± 1 yr old, an abrupt decrease in mean arterial pressure (MAP) was induced nonpharmacologically by releasing a unilateral arterial thigh cuff (300 Torr) after 9 min of resting leg ischemia under two conditions: 1) ABR and CBR deactivation (control) and 2) ABR deactivation. Under control conditions, cuff release decreased MAP by 13 ± 1 mmHg, whereas HR increased 11 ± 2 beats/min. During ABR deactivation, neck suction was gradually applied to maintain carotid sinus transmural pressure during the initial 20 s after cuff release (suction). This attenuated the increase in HR (6 ± 1 beats/min) and caused a greater decrease in MAP (18 ± 2 mmHg, P < 0.05). Furthermore, estimated cardiac baroreflex responsiveness (ΔHR/ΔMAP) was significantly reduced during suction compared with control conditions. These findings suggest that the carotid baroreceptors contribute more importantly to the reflex control of HR than previously reported in healthy individuals.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume284
Issue number2 53-2
StatePublished - Feb 1 2003

Fingerprint

Baroreflex
Heart Rate
Arterial Pressure
Suction
Carotid Sinus
Reflex
Blood Pressure
Pressoreceptors
Dizziness
Denervation
Thigh
Leg
Neck
Ischemia
Pressure

Keywords

  • Aortic baroreceptors
  • Blood pressure
  • Carotid baroreceptors
  • Hypotension
  • Neck suction

ASJC Scopus subject areas

  • Physiology

Cite this

New insights into differential baroreflex control of heart rate in humans. / Fadel, P. J.; Strømstad, M.; Wray, D. W.; Smith, S. A.; Raven, P. B.; Secher, N. H.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 284, No. 2 53-2, 01.02.2003.

Research output: Contribution to journalArticle

Fadel, P. J. ; Strømstad, M. ; Wray, D. W. ; Smith, S. A. ; Raven, P. B. ; Secher, N. H. / New insights into differential baroreflex control of heart rate in humans. In: American Journal of Physiology - Heart and Circulatory Physiology. 2003 ; Vol. 284, No. 2 53-2.
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