Document Detail


Exercise-induced ventilatory abnormalities in orthotopic heart transplant patients.
MedLine Citation:
PMID:  9361243     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
STUDY OBJECTIVE: The purpose of this investigation was to compare multiple ventilatory responses of heart transplant patients (HTP) with normal subjects (NL) at rest, at absolute and relative submaximal exercise levels, and at peak exercise. DESIGN: Ten male HTP and 10 matched NL were tested under similar conditions on a treadmill with the use of an incremental protocol to symptom-limited maximal levels while breath-by-breath measurements of gas exchange and ventilation were obtained. RESULTS: At an absolute carbon dioxide (VCO2) level of 1 L.min-1, minute ventilation (VE) was significantly higher in HTP compared with NL (38.4 +/- 1.9 versus 29.3 +/- 0.9 L.min-1). However, when compared at similar relative levels (i.e., 40% and 60% of the peak oxygen consumption [VO2 peak]), VE was found to be significantly higher in NL compared with HTP (25.5 +/- 1.4 versus 21.2 +/- 1.0 L.min-1 at 40%; 39.9 +/- 3.1 versus 32.1 +/- 2.0 L.min-1 at 60%, respectively). The reduced VE was the result of a significantly lower tidal volume (VT) in HTP compared with NL at 40% (1.14 +/- 0.08 versus 1.33 +/- 0.05 L) and 60% (1.40 +/- 0.10 versus 1.85 +/- 0.06 L) of VO2 peak, since breathing frequency (BF) was not different between the groups at these levels. CONCLUSIONS: These data demonstrate that HTP have abnormal ventilatory responses to incremental exercise that are largely explained by a diminished VT response. While mechanical factors known to affect VT cannot be ignored, it is likely that the abnormal VT response of HTP during exercise is secondary to respiratory muscle weakness and may be due to hypoperfusion, long-term deconditioning, and/or the long-term use of corticosteriods.
Authors:
P H Brubaker; S C Brozena; D L Morley; J D Walter; M J Berry
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation     Volume:  16     ISSN:  1053-2498     ISO Abbreviation:  J. Heart Lung Transplant.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-12-18     Completed Date:  1997-12-18     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9102703     Medline TA:  J Heart Lung Transplant     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1011-7     Citation Subset:  IM    
Affiliation:
Department of Medicine, Wake Forest University, Winston-Salem, N.C. 27109, USA.
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Pressure
Carbon Dioxide / metabolism
Case-Control Studies
Exercise Test
Exercise Tolerance / physiology
Fatigue / physiopathology
Glucocorticoids / therapeutic use
Heart Rate
Heart Transplantation / physiology*
Humans
Male
Muscle Weakness / physiopathology
Oxygen Consumption / physiology
Physical Exertion / physiology*
Physical Fitness / physiology
Prednisone / therapeutic use
Pulmonary Gas Exchange / physiology
Pulmonary Ventilation / physiology
Respiration / physiology*
Respiratory Muscles / physiology
Rest / physiology
Tidal Volume / physiology
Chemical
Reg. No./Substance:
0/Glucocorticoids; 124-38-9/Carbon Dioxide; 53-03-2/Prednisone

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


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