Document Detail


Ventilatory response to exercise correlates with impaired heart rate variability in patients with chronic congestive heart failure.
MedLine Citation:
PMID:  9708664     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In chronic congestive heart failure (CHF) an overactivity of muscle ergoreceptors and peripheral chemoreceptors may lead to an increased ventilatory response to exercise and contribute to the autonomic imbalance. The analysis of heart rate variability (HRV), which is a reliable method of studying autonomic regulations within the cardiovascular system, showed depressed HRV indexes in CHF, but predictors of abnormal HRV pattern in CHF remain controversial. Considering a common mechanism involved in generation of both abnormal ventilation and autonomic dysfunction in CHF, we hypothesized that impaired ventilation may be better than other variables of CHF severity in determining HRV parameters. Seventy-two patients with CHF (57+/-9 years, ejection fraction: 28+/-11%) underwent cardiopulmonary exercise testing; the relation between ventilation and carbon dioxide production (VE/VCO2) was used as an index of the ventilatory response to exercise. Time and frequency-domain measurements of HRV were derived from 24-hour electrocardiographic monitoring. Patients had reduced exercise tolerance with abnormal ventilatory response (peak oxygen consumption [VO2max]: 17.8+/-5.5 ml/kg/min, VE/VCO2: 36.0+/-9.8). Correlations were found between HRV measures and etiology, New York Heart Association (NYHA) functional class, and VO2max, but the strongest relation was observed for VE/VCO2 slope (r values from -0.33 to -0.65, p <0.01). In the multiple regression analysis only VE/VCO2 was found to correlate independently with all HRV measurements. To investigate the role of peripheral chemoreceptor overactivity as the mechanism of autonomic imbalance and the increased ventilatory response to exercise, we assessed peripheral chemosensitivity in 22 patients (mean value of peripheral chemosensitivity: 0.62+/-0.34 L/min/%SaO2, significantly higher than in normal controls, mean value: 0.29+/-0.20 L/min/%SaO2 in our laboratory). The activity of the peripheral chemoreflex inversely correlated with all parameters of HRV. Increased ventilatory response to exercise correlated with depressed HRV measures in patients with CHF better than other clinical variables. An important role of the increased peripheral chemosensitivity in this relation may be relevant, being also a potential link between functional severity and sympathovagal imbalance in CHF.
Authors:
P Ponikowski; T P Chua; M Piepoli; W Banasiak; S D Anker; R Szelemej; W Molenda; K Wrabec; A Capucci; A J Coats
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The American journal of cardiology     Volume:  82     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1998 Aug 
Date Detail:
Created Date:  1998-09-01     Completed Date:  1998-09-01     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  338-44     Citation Subset:  AIM; IM; S    
Affiliation:
Cardiac Medicine Department, Imperial College National Heart and Lung Institute, London, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Administration, Inhalation
Autonomic Nervous System / physiopathology
Chemoreceptor Cells / physiopathology
Chronic Disease
Electrocardiography, Ambulatory
Exercise / physiology*
Female
Heart Failure / physiopathology*
Heart Rate / physiology*
Humans
Male
Middle Aged
Multivariate Analysis
Nitrogen / administration & dosage,  diagnostic use
Predictive Value of Tests
Respiration / physiology*
Respiratory Function Tests
Chemical
Reg. No./Substance:
7727-37-9/Nitrogen

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


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