Document Detail


Chronic heart failure, chronotropic incompetence, and the effects of beta blockade.
MedLine Citation:
PMID:  16159968     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To establish the prevalence of chronotropic incompetence in a cohort of patients with chronic heart failure (CHF) taking modern medications for heart failure, and whether this affected exercise capacity and predicted prognosis. METHODS: Heart rate response to exercise was examined in 237 patients with CHF in sinus rhythm, who were compared with 118 control volunteers. The percentage of maximum age predicted peak heart rate (%Max-PPHR) and percentage heart rate reserve (%HRR) were calculated, with a cut off of < 80% as the definition of chronotropic incompetence for both. Patients were followed up for an average (SD) of 2.8 (9) years. Mortality was related to peak oxygen consumption (pVo2), and the presence or absence of chronotropic incompetence. RESULTS: %Max-PPHR < 80% identified 103 (43%) and %HRR < 80% identified 170 patients (72%) as having chronotropic incompetence. Chronotropic incompetence was more common in patients taking beta blockers than in those not taking beta blockers as assessed by both methods (80 (49%) v 23 (32%) by %Max-PPHR and 123 (75%) v 47 (64%) by %HRR, respectively). Patients with chronotropic incompetence by either method had a lower pVo2 than those without. These differences remained significant for both patients taking and not taking a beta blocker. %HRR, Max-PPHR%, and HRR were related to New York Heart Association class and correlated with pVo2. There was no difference in the slopes relating heart rate to pVo2 between patients with and those without chronotropic incompetence (6.1 (1.7) v 5.1 (1.8), p = 0.34). During an average 2.8 year follow up 40 patients (17%) died. In Cox proportional hazard models, pVo2 was the most powerful predictor of survival and neither measure of chronotropic incompetence independently predicted outcome. CONCLUSIONS: pVo2 is a powerful marker of prognosis for patients with CHF whether they are taking beta blockers or not. A low heart rate response to exercise in patients with CHF correlates with worse exercise tolerance but is unlikely to contribute to exercise impairment.
Authors:
K K A Witte; J G F Cleland; A L Clark
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Publication Detail:
Type:  Journal Article     Date:  2005-09-13
Journal Detail:
Title:  Heart (British Cardiac Society)     Volume:  92     ISSN:  1468-201X     ISO Abbreviation:  Heart     Publication Date:  2006 Apr 
Date Detail:
Created Date:  2006-03-15     Completed Date:  2006-05-08     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  9602087     Medline TA:  Heart     Country:  England    
Other Details:
Languages:  eng     Pagination:  481-6     Citation Subset:  AIM; IM    
Affiliation:
University of Hull, Hull, UK. klauswitte@hotmail.com
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / therapeutic use*
Aged
Cohort Studies
Exercise / physiology*
Exercise Tolerance / physiology
Female
Heart Failure / drug therapy*
Heart Rate / physiology*
Humans
Male
Middle Aged
Oxygen Consumption / physiology*
Predictive Value of Tests
Prognosis
Survival Analysis
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists
Comments/Corrections

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


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