Document Detail


Heart rate response to graded exercise correlates with aerobic and ventilatory capacity in patients with heart failure.
MedLine Citation:
PMID:  15704528     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Autonomic dysfunction and reduced exercise tolerance are typical features of patients with congestive heart failure (CHF). Baro-chemoreflex balance and organ response may have a common role in conditioning exercise tolerance, ventilation, and chronotropic competence in patients with CHF. HYPOTHESIS: We tested the hypothesis that there is a relationship between functional capacity and chronotropic competence to exercise in CHF. METHODS: In all, 48 stable outpatients with CHF (age 65 +/- 10 years, 41 men, NYHA class 2.1 +/- 0, ejection fraction 31 +/- 7%, peak VO2 16 +/- 4 ml/kg/min) performed cardiopulmonary exercise testing (CPX). Heart rate (HR) response to exercise was assessed by the chronotropic index (CRI). The CRI was calculated by the following formula: CRI = peak HR - rest HR/220 - age - rest HR x 100 (normal value > 80%). The relationship of CRI to peak oxygen consumption (VO2) and ventilation/carbon dioxide production (VE/VCO2) ratio was examined. A group of 33 healthy controls underwent CPX as well. RESULTS: The CRI correlated directly with peak VO2 (r = 0.638, p < 0.001) and inversely with VE/VCO2 (r = -0.492, p < 0.001) in patients with CHF. A CRI < 78% identified patients with CHF and a peak VO2 < 20 ml/kg/min, area under the receiver operating curve (AUROC): 0.76, 95% confidence interval (CI) 0.60-0.92. A CRI < 74% predicted exercise hyperventilation in CHF (AUROC: 0.71 for VE/VCO2 > 30, 95% CI 0.53-0.88). The CRI was not significantly related either to peak VO2 or to VE/VCO2 in the control group. CONCLUSIONS: In patients with mild to moderate CHF, CRI correlates with functional capacity. This relationship adds new data on pathophysiologic grounds and supports the routine incorporation of CRI into CPX interpretation.
Authors:
Alessandro Vallebona; Guido Gigli; Sandro Orlandi; Giorgio Reggiardo
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical cardiology     Volume:  28     ISSN:  0160-9289     ISO Abbreviation:  Clin Cardiol     Publication Date:  2005 Jan 
Date Detail:
Created Date:  2005-02-11     Completed Date:  2005-05-17     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7903272     Medline TA:  Clin Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  25-9     Citation Subset:  IM    
Affiliation:
Department of Cardiology, Heart Failure Unit, Rapallo Hospital, Rapallo (Genoa), Italy. avallebona@as14.liguria.it
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MeSH Terms
Descriptor/Qualifier:
Aged
Case-Control Studies
Exercise / physiology*
Exercise Tolerance / physiology*
Female
Heart Failure / physiopathology*
Heart Rate / physiology*
Humans
Lung Volume Measurements
Male
Middle Aged
Oxygen Consumption / physiology*
Pulmonary Ventilation / physiology*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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