Vasomotor responses to decreased venous return: effects of cardiac deafferentation in humans

C.J. Weisbrod, Leonard Arnolda, Doug Mckitrick, J.G. O'Driscoll, Kathleen Potter, Daniel Green

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10 Citations (Scopus)

Abstract

We compared haemodynamic and peripheral vasomotor responses to lower body negative pressure (LBNP) in cardiac transplant recipients who had undergone bicaval anastomoses, involving right atrial deafferentation (−RA), and the conventional procedure in which some atrial baroreceptor afferents remain intact (+RA). We measured mean forearm blood flow (FBF) responses using Doppler/ultrasound during three randomised trials involving 0 (baseline), −20 and −40 mmHg LBNP in 15 transplant recipients (9 −RA, 6 +RA) and in eight healthy matched controls. A significant effect of LBNP on FBF existed between control and transplant groups (P <0.05; two-way ANOVA). Mild LBNP (−20 mmHg), significantly decreased FBF by 29.7 ± 10.0% relative to baseline in +RA subjects (P <0.05), whereas the 17.7 ± 10.3% decrease in −RA subjects was not significant. In response to −40 mmHg LBNP, FBF significantly decreased in control (42.4 ± 4.6%, P <0.05) and +RA subjects (33.3 ± 11.4%, P <0.05) with no significant change in the −RA group. The response of systolic blood pressure (SBP) to −40 mmHg significantly differed between groups (P <0.05): −RA subjects decreased significantly (P <0.05) whilst the decrease in SBP in +RA subjects did not achieve significance and control subjects exhibited an increase. The heart rate increase from baseline to −40 mmHg was significantly attenuated in −RA relative to controls and the +RA group (P <0.05). The present study demonstrates that atrial deafferentation impairs reflex vasomotor control of the circulation in response to low- and high-level LBNP, indicating that atrial deafferentation may contribute to abnormal arterial pressure regulation.
Original languageEnglish
Pages (from-to)919-927
JournalThe Journal of Physiology
Volume560
Issue number3
DOIs
Publication statusPublished - 2004

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