Autonomic cardiovascular regulation in subjects with acute mountain sickness
1 Centre de Recherche, Hôpital du Sacré-Coeur, Montreal, Quebec, Canada; 2 Division of Cardiology, 3 Service of Bioengineering, 5 Division of Respiratory Medicine, and 7 Department of Radiology, Salvatore Maugeri Foundation, Istituto Scientifico IRCCS Veruno, Verona; and 4 Unit of Respiratory Medici...
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Published in | American journal of physiology. Heart and circulatory physiology Vol. 289; no. 6; pp. H2364 - H2372 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.12.2005
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Subjects | |
Online Access | Get full text |
ISSN | 0363-6135 1522-1539 |
DOI | 10.1152/ajpheart.00004.2005 |
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Summary: | 1 Centre de Recherche, Hôpital du Sacré-Coeur, Montreal, Quebec, Canada; 2 Division of Cardiology, 3 Service of Bioengineering, 5 Division of Respiratory Medicine, and 7 Department of Radiology, Salvatore Maugeri Foundation, Istituto Scientifico IRCCS Veruno, Verona; and 4 Unit of Respiratory Medicine, San Raffaele University Hospital, Milan, Italy; and 6 Division of Physiology, Department of Medicine, University of California, San Diego, California
Submitted 4 January 2005
; accepted in final form 25 July 2005
The aims of this study were 1 ) to evaluate whether subjects suffering from acute mountain sickness (AMS) during exposure to high altitude have signs of autonomic dysfunction and 2 ) to verify whether autonomic variables at low altitude may identify subjects who are prone to develop AMS. Forty-one mountaineers were studied at 4,559-m altitude. AMS was diagnosed using the Lake Louise score, and autonomic cardiovascular function was explored using spectral analysis of R-R interval and blood pressure (BP) variability on 10-min resting recordings. Seventeen subjects (41%) had AMS. Subjects with AMS were older than those without AMS ( P < 0.01). At high altitude, the low-frequency (LF) component of systolic BP variability (LF SBP ) was higher ( P = 0.02) and the LF component of R-R variability in normalized units (LF RR NU) was lower ( P = 0.001) in subjects with AMS. After 3 mo, 21 subjects (43% with AMS) repeated the evaluation at low altitude at rest and in response to a hypoxic gas mixture. LF RR NU was similar in the two groups at baseline and during hypoxia at low altitude but increased only in subjects without AMS at high altitude ( P < 0.001) and did not change between low and high altitude in subjects with AMS. Conversely, LF SBP increased significantly during short-term hypoxia only in subjects with AMS, who also had higher resting BP ( P < 0.05) than those without AMS. Autonomic cardiovascular dysfunction accompanies AMS. Marked LF SBP response to short-term hypoxia identifies AMS-prone subjects, supporting the potential role of an exaggerated individual chemoreflex vasoconstrictive response to hypoxia in the genesis of AMS.
hypoxia; autonomic nervous system; heart rate; blood pressure
Address for reprint requests and other correspondence: P. A. Lanfranchi, Centre de Recherche, Hôpital du Sacré-Coeur, 5400 boul. Gouin Ouest, Montreal, QC, Canada H4J 1C5 (e-mail: paola-lanfranchi{at}umontreal.ca ) |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0363-6135 1522-1539 |
DOI: | 10.1152/ajpheart.00004.2005 |