Document Detail


Impact of exercise training on ventricular properties in a canine model of congestive heart failure.
MedLine Citation:
PMID:  9087615     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exercise training improves functional class in patients with chronic heart failure (CHF) via effects on the periphery with no previously documented effect on intrinsic left ventricular (LV) properties. However, because methods used to evaluate in vivo LV function are limited, it is possible that some effects of exercise training on the failing heart have thus far eluded detection. Twelve dogs were instrumented for cardiac pacing and hemodynamic recordings. Hearts were paced rapidly for 4 wk. Six of the dogs received daily treadmill exercise (CHF(EX), 4.4 km/h, 2 h/day) concurrent with rapid pacing, while the other dogs remained sedentary (CHFs). Hemodynamic measurements taken in vivo at the end of 4 wk revealed relative preservation of maximum rate of pressure rise (2,540 +/- 440 vs. 1,720 +/- 300 mmHg/s, P < 0.05) and LV end-diastolic pressure (9 +/- 5 vs. 19 +/- 4 mmHg, P < 0.05) in CHF(EX) compared with CHFs. The hearts were then isolated and cross perfused for in vitro measurement of isovolumic pressure-volume relations; these results were compared with those of six normal dogs (N). Systolic function was similarly depressed in both groups of pacing animals [end-systolic elastance (Ees) values of 1.66 +/- 0.47 in CHFs, 1.77 +/- 0.38 in CHF(EX), and 3.05 +/- 0.81 mmHg/ml in N, with no changes in volume axis interceptors of the end-systolic pressure-volume relationship]. The diastolic myocardial stiffness constant, k, was elevated in CHFs and was normalized by exercise training (32 +/- 3 in CHFs, 21 +/- 3 in CHF(EX), 20 +/- 4 in N). Thus daily exercise training preserved in vivo hemodynamics during 4 wk of rapid cardiac pacing and was accompanied by a significant change in diastolic myocardial stiffness in vitro. These findings suggest that changes in heart function may contribute to the overall beneficial hemodynamic effects of exercise training in CHF by a significant effect on diastolic properties.
Authors:
K Todaka; J Wang; G H Yi; M Knecht; R Stennett; M Packer; D Burkhoff
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  272     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Mar 
Date Detail:
Created Date:  1997-04-28     Completed Date:  1997-04-28     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1382-90     Citation Subset:  IM    
Affiliation:
Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Animals
Body Weight
Collagen / metabolism
Coronary Circulation
Diastole
Dogs
Heart / physiopathology
Heart Failure / physiopathology*
Heart Rate
Hemodynamics*
Models, Cardiovascular
Myocardium / metabolism
Organ Size
Physical Conditioning, Animal*
Reference Values
Systole
Ventricular Function, Left*
Grant Support
ID/Acronym/Agency:
IR-29-HL-51885-01/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
9007-34-5/Collagen

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


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