Document Detail

Chronotropic incompetence response to exercise in congestive heart failure, relationship with the cardiac autonomic status.
MedLine Citation:
PMID:  11380533     Owner:  NLM     Status:  MEDLINE    
In chronic congestive heart failure (CHF), attenuated heart rate response to exercise, a manifestation of chronotropic incompetence (CI), contributes to limiting exercise capacity. The present study was thus conducted to evaluate the respective role of chronic attenuation of cardiac vagal tone associated with depressed baroreflex sensitivity or affected cardiac sympathetic responsiveness in CHF patients with CI. Spontaneous cardiac baroreflex sensitivity (BRS) assessed by sequence method and spectral- and time-domain analysis of heart rate variability (HRV) were analysed in 21 chronic CHF patients. All patients performed a symptom-limited exercise test with measurement of gas exchange. Chronic incompetence which was defined as failure to achieve > or =80% of the heart rate reserve (%HRR) given by (HRpeak - HRrest)/(predictive maximal heart rate - HRrest) was observed in 14 (66%) patients. There was no significant difference in age, heart rate, peak oxygen uptake or left ventricular ejection fraction between the patients with and without CI. Although there was no significant difference in BRS, low frequency power of HRV in normalized units (LFnu) and SDNN were significantly lower in CI patients. Percentage of HRR correlated significantly with LFnu on 15 min (r=0.64, P<0.005) and, with LFnu on 24 h (r=0.52, P<0.01), SDNN (r=0.48, P=0.03) and SDANN (r=0.48, P=0.03), but not BRS (r=0.04, P=NS). Autonomic nervous system derangement is a complex process in CHF. The role of basal depressed cardiac sympathetic tone seems to contribute more closely than depressed baroreflex sensitivity to the impaired heart rate response to exercise frequently observed in CHF patients.
F Roche; V Pichot; A Da Costa; K Isaaz; F Costes; T Dall'Acqua; D Duverney; J R Lacour; J C Barthélémy
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Clinical physiology (Oxford, England)     Volume:  21     ISSN:  0144-5979     ISO Abbreviation:  Clin Physiol     Publication Date:  2001 May 
Date Detail:
Created Date:  2001-05-30     Completed Date:  2001-07-12     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8309768     Medline TA:  Clin Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  335-42     Citation Subset:  IM    
Laboratoire de Physiologie GIP-Exercice, Service d'Exploration Fonctionnelle CardioRespiratoire, CHU Nord, Faculté de Médecine Jacques Lisfranc, Université Jean Monnet, Saint-Etienne, France.
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MeSH Terms
Age Factors
Autonomic Nervous System / physiology
Exercise / physiology*
Heart Failure / physiopathology*
Heart Rate / physiology*
Middle Aged
Oxygen / metabolism
Ventricular Function, Left
Reg. No./Substance:

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