Document Detail

Mechanisms of periodic breathing during exercise in patients with chronic heart failure.
MedLine Citation:
PMID:  18187746     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Periodic breathing (PB) in heart failure (HF) is attributed to many factors, including low cardiac output delaying the time it takes pulmonary venous blood to reach the central and peripheral chemoreceptors, low lung volume, lung congestion, augmented chemoreceptor sensitivity, and the narrow difference between eupneic carbon dioxide tension and apneic/hypoventilatory threshold. METHODS AND RESULTS: We measured expired gases, ventilation, amplitude, and duration of PB in 23 patients with PB during progressive exercise tests done with 0 mL, 250 mL, or 500 mL of added dead space. Periodicity of PB remained constant despite heart rate, oxygen consumption, and minute ventilation increasing. Within each PB cycle, starting from the beginning of exercise, the largest (peak) tidal volume approached maximum observed tidal volume, while the smallest (nadir) tidal volume increased as exercise power output increased. PB ceased when nadir tidal volume reached peak tidal volume. End-tidal carbon dioxide increased with added dead space, and PB ceased progressively earlier during the exercise done with increased dead space. CONCLUSION: Circulatory delay does not contribute to the PB observed in exercising HF patients. The pattern of gradually increasing nadir tidal volume during exercise and the effect of dead space on both PB ceasing and end-tidal carbon dioxide suggest that low tidal volume and carbon dioxide apnea threshold are important contributors to PB that occurs during exercise in HF.
Piergiuseppe Agostoni; Anna Apostolo; Richard K Albert
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Chest     Volume:  133     ISSN:  0012-3692     ISO Abbreviation:  Chest     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2008-01-11     Completed Date:  2008-03-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  United States    
Other Details:
Languages:  eng     Pagination:  197-203     Citation Subset:  AIM; IM    
Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia, Università di Milano, Via Parea 4, 20138 Milan, Italy.
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MeSH Terms
Exercise / physiology*
Heart Failure / physiopathology*
Respiratory Dead Space

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

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