Document Detail


Noninvasive evaluation of skeletal muscle oxidative metabolism after heart transplant.
MedLine Citation:
PMID:  16888448     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: The main aim of the present study was to investigate skeletal muscle oxidative metabolism in heart transplant recipients (HTR) by noninvasive tools. METHODS: Twenty male HTR (age 50.4 +/- 2.6 yr; mean +/- SE) and 17 healthy untrained age-matched controls (CTRL) performed an incremental exercise (IE) and a series of constant-load (CLE) moderate-intensity exercise tests on a cycloergometer. The following variables were determined: heart rate (HR); breath-by-breath pulmonary O2 uptake (VO2); and skeletal muscle (vastus lateralis) oxygenation indices by continuous-wave near-infrared spectroscopy. Changes in concentration of deoxygenated hemoglobin (Hb) and myoglobin (Mb) (Delta[deoxy(Hb + Mb)]), expressed as a fraction of values obtained during a transient limb ischemia, were taken as an index of skeletal muscle O2 extraction. "Peak" values were determined at exhaustion during IE. Kinetics of adjustment of variables were determined during CLE. RESULTS: VO2peak, HRpeak, and Delta[deoxy(Hb + Mb)] peak were significantly lower in HTR than in CTRL (17.1 +/- 0.7 vs 34.0 +/- 1.9 mL.kg(-1).min(-1), 133.8 +/- 3.8 vs 173.0 +/- 4.8 bpm, and 0.42 +/- 0.03 vs 0.58 +/- 0.04, respectively). In HTR, Delta[deoxy(Hb + Mb)] increase at submaximal workloads was steeper than in CTRL, suggesting an impaired O2 delivery to skeletal muscles, whereas the lower Delta[deoxy(Hb + Mb)] peak values suggest an impaired capacity of O2 extraction at peak exercise. VO2 and HR kinetics during CLE were significantly slower in HTR than in CTRL, whereas, unexpectedly, no significant differences were found for Delta[deoxy(Hb+Mb)] kinetics (mean response time: 21.3 +/- 1.1 vs 20.2 +/- 1.2 s). CONCLUSION: The findings confirm the presence of both "central" (cardiovascular) and "peripheral" (at the skeletal muscle level) impairments to oxidative metabolism in HTR. The noninvasiveness of the measurements will allow for serial evaluation of the patients, in the presence and/or absence of rehabilitation programs.
Authors:
Francesca Lanfranconi; Emma Borrelli; Alessandra Ferri; Simone Porcelli; Massimo Maccherini; Mario Chiavarelli; Bruno Grassi
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  38     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-08-04     Completed Date:  2006-12-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1374-83     Citation Subset:  IM; S    
Affiliation:
Department of Science and Biomedical Technologies, University of Milan, Milan, Italy.
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MeSH Terms
Descriptor/Qualifier:
Case-Control Studies
Exercise / physiology*
Exercise Test
Heart Rate / physiology
Heart Transplantation*
Hemoglobins / analysis
Humans
Least-Squares Analysis
Male
Middle Aged
Muscle, Skeletal / metabolism*
Myoglobin / analysis
Oxygen Consumption / physiology*
Spectroscopy, Near-Infrared
Chemical
Reg. No./Substance:
0/Hemoglobins; 0/Myoglobin

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


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