| Impaired pulmonary diffusion during exercise in patients with chronic heart failure. | |
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MedLine Citation:
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PMID: 10500041 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Pulmonary diffusion is impaired at rest in patients with chronic heart failure (CHF) and has been implicated in the generation of symptoms and exercise intolerance. The aim of this study was to determine whether pulmonary diffusion is impaired during exercise in CHF, to examine its relationship to pulmonary blood flow, and to consider its functional significance in relation to metabolic gas exchange. METHODS AND RESULTS: Carbon monoxide transfer factor (TLCO) and pulmonary blood flow (Q(C)) were measured by a rebreathe technique at rest and during steady-state cycling at 30 W in 24 CHF patients and 10 control subjects. Both patients and control subjects were able to raise TLCO and Q(C) during exercise. However, the patient group had a lower diffusion for a given blood flow (TLCO/Q(C)) both at rest (3.6+/-0.16 and 4.8+/-0.23 mL x L(-1) x mm Hg(-1); P<0.001) and during exercise (2.8+/-0.16 and 3.4+/-0.13 mL x L(-1) x mm Hg(-1) for CHF patients and control subjects, respectively; P<0.05). TLCO/Q(C) was related to the ventilatory equivalent for carbon dioxide (VEVCO(2)) production at 30 W (TLCO/Q(c) versus VEVCO(2), r = -0.58, P<0.01) and to peak exercise oxygen consumption measured during a progressive test (TLCO/Qc versus VO(2peak), r = 0.57, P<0.01) in these patients. CONCLUSIONS: Patients with CHF are able to recruit reserves of TLCO and Q(C) during exercise. However, the TLCO/Q(C) ratio is consistently impaired in these patients and relates to both exercise hyperpnea and peak exercise oxygen consumption. Whether this impairment in alveolar gas exchange is reversible in CHF and therefore is a potential target for therapy has yet to be determined. |
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Authors:
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A A Smith; P J Cowburn; M E Parker; M Denvir; S Puri; K R Patel; J G Cleland |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Circulation Volume: 100 ISSN: 1524-4539 ISO Abbreviation: Circulation Publication Date: 1999 Sep |
Date Detail:
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Created Date: 1999-10-20 Completed Date: 1999-10-20 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0147763 Medline TA: Circulation Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 1406-10 Citation Subset: AIM; IM; S |
Affiliation:
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Clinical Research Initiative in Heart Failure, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Cardiac Output, Low
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physiopathology* Chronic Disease Exercise* Exercise Test Homeostasis Humans Lung / physiopathology Male Middle Aged Pulmonary Circulation Pulmonary Diffusing Capacity* Rest |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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