| Cardiovascular and neuroendocrine responses to water immersion in compensated heart failure. |
| Research field: | Cardiovascular physiology |
| Authors: | Gabrielsen A., Sørensen V.B., Pump B., Galatius S., Videbæk R., Bie P., Warberg J., Christensen N.J., Wroblewski H., Kastrup J., Norsk P. |
Address of presenting
author: | Anders Gabrielsen, MD
Danish Aerospace Medical Centre of Research,
National University Hospital 7805,
20 Tagensvej,
2200-DK Copenhagen,
Denmark.
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| E-mail: | agabrielsen.damec@post.uni2.dk |
| Phone: | +45 35 36 14 64 |
| Fax: | +45 35 36 22 82 |
| Text of abstract |
Introduction
The hypothesis was tested that cardiovascular control and suppression of sympathetic nervous activity and of renin and arginine vasopressin release in response to central blood volume expansion is blunted in compensated heart failure (HF).
Methods
Nine patients with HF evaluated for cardiac transplantation and receiving medical treatment (NYHA class II-III, ejection fraction (EF)=0.28±0.02 (mean±SEM)) and 10 age matched controls (EF=0.68±0.03) underwent 30 min of thermoneutral (34.7±0.02 degrees C) water immersion (WI) to the Xiphoid process. The experimental protocol was approved by the Ethical Committee of Copenhagen (KF 01-099/97), and informed consent was obtained from all subjects.
Results
WI increased (p<0.05) central venous pressure by 3.7±0.6 (controls) and 3.2±0.4 mmHg (HF) and stroke volume index by 12.2±2.1 (controls) and 7.2±2.1 ml beat-1 m-2 (HF), and systemic vascular resistance decreased (p<0.05) similarly by 365±66 (controls) and 582±227 dyn sec cm-5 (HF), respectively. In response to WI, forearm subcutaneous vascular resistance decreased by 19±7 % (p<0.05) in the control subjects but did not change in HF. Forearm muscle vascular resistance did not change in either group in response to WI and increased only in the control subjects by 44±18 % during recovery (p<0.05). The decrease in heart rate during WI was blunted in HF compared to controls. In contrast, release of norepinephrine, renin and arginine vasopressin were suppressed during WI to a very similar extent in the two groups.
Conclusions
These results suggest that the reflex control of forearm vascular beds and heart rate are blunted in compensated HF, but that the baroreflex-mediated control of systemic vascular resistance and release of neuroendocrine mediators during central blood volume expansion are preserved.
References
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| Keywords: | sympathetic nervous activity, arginine vasopressin, renin-angiotensin system, endothelin, baroreceptors |