| Effects of cold exposure on submaximal exercise performance and adrenergic activation in patients with congestive heart failure and the effects of beta-adrenergic blockade (carvedilol or metoprolol). | |
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MedLine Citation:
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PMID: 12943875 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Patients with congestive heart failure (CHF) exhibit a decrease in maximal exercise capacity in response to a cold environment. The aim of this study was to further investigate the impact of cold exposure on submaximal exercise capacity, systemic adrenergic drive, and the effects of long-term beta-adrenergic blockade on these parameters. Thirty-three patients with CHF, with exercise limited by dyspnea and left ventricular ejection fraction of 26 +/- 4%, were randomized to receive metoprolol or carvedilol for 6 months. The observations were compared with 12 age-matched healthy volunteers. Maximal exercise performance with gas exchange analyses were assessed using a ramp protocol, and endurance capacity was measured using 2 constant-load exercise tests performed randomly at 20 degrees C and -8 degrees C. Healthy volunteers increased their submaximal exercise time by 20% (1,353 +/- 455 [20 degrees C] vs 1,635 +/- 475 seconds [-8 degrees C]; p <0.05), whereas patients with CHF exhibited a 21% decrease in exercise time (1,182 +/- 549 [20 degrees C] vs 931 +/- 524 seconds [-8 degrees C]; p <0.05) at -8 degrees C. Beta blockers increased submaximal exercise duration at 20 degrees C (+261 +/- 617 seconds; p <0.05) and -8 degrees C (+374 +/- 729 seconds; p <0.05). Norepinephrine increased to a greater extent at 4 minutes and at the time of exhaustion (at -8 degrees C) only in patients with CHF. Beta-adrenergic blockade caused no significant decrease in plasma norepinephrine levels. Patients with symptomatic CHF exhibited a significant decrease in submaximal exercise time in response to moderate cold exposure. Beta-blocker therapy with either metoprolol or carvedilol significantly increases submaximal exercise time and attenuates the impact of cold exposure on functional capacity. |
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Authors:
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Martine Blanchet; Anique Ducharme; Normand Racine; Jean Lucien Rouleau; Jean Claude Tardif; Martin Juneau; Johanne Marquis; Lucie Larivée; Anil Nigam; Anick Fortier; Michel White |
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Publication Detail:
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Type: Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The American journal of cardiology Volume: 92 ISSN: 0002-9149 ISO Abbreviation: Am. J. Cardiol. Publication Date: 2003 Sep |
Date Detail:
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Created Date: 2003-08-28 Completed Date: 2003-10-07 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 0207277 Medline TA: Am J Cardiol Country: United States |
Other Details:
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Languages: eng Pagination: 548-53 Citation Subset: AIM; IM |
Affiliation:
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Research Center, Montreal Heart Institute, Quebec, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Antagonists
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pharmacology,
therapeutic use* Aged Blood Gas Analysis Carbazoles / pharmacology, therapeutic use* Case-Control Studies Cold Temperature / adverse effects* Dyspnea / etiology Exercise Test / drug effects Exercise Tolerance / drug effects* Female Heart Failure / complications, drug therapy*, metabolism, physiopathology* Humans Male Metoprolol / pharmacology, therapeutic use* Middle Aged Norepinephrine / blood Physical Endurance Propanolamines / pharmacology, therapeutic use* Prospective Studies Receptors, Adrenergic / drug effects*, physiology* Single-Blind Method Stroke Volume / drug effects |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Antagonists; 0/Carbazoles; 0/Propanolamines; 0/Receptors, Adrenergic; 37350-58-6/Metoprolol; 51-41-2/Norepinephrine; 72956-09-3/carvedilol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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