Document Detail


Effect of exercise on left ventricular-arterial coupling assessed in the pressure-volume plane.
MedLine Citation:
PMID:  8098914     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The left ventricle (LV) and arterial system are nearly optimally coupled to produce stroke work (SW) at rest. However, the effect of exercise on the coupling between the LV and arterial system has not been directly determined. We evaluated 11 dogs who were instrumented to determine LV volume from three diameters. The LV end-systolic pressure (Pes)-volume (Ves) relation was determined by transient caval occlusion at rest and while the animals ran at 5-7 mph on a treadmill. During exercise, the Pes-Ves relation was shifted toward the left and the slope [end-systolic elastance (Ees)] increased from 7.7 +/- 2.8 to 12.7 +/- 4.2 (SD) mmHg/ml (P < 0.05). The arterial end-systolic elastance (Ea), calculated as Pes divided by stroke volume, increased during exercise (8.8 +/- 3.0 to 10.9 +/- 4.7 mmHg/ml, P < 0.05). The ratio of Ees to Ea increased during exercise from 0.89 +/- 0.31 to 1.27 +/- 0.12 (P < 0.05). The portion of the pressure-volume area expressed as SW increased during exercise from 0.63 +/- 0.07 to 0.69 +/- 0.10 (P < 0.05). After adrenergic blockade, the Ees-to-Ea ratio was not significantly altered during exercise (0.90 +/- 0.24 vs. 0.83 +/- 0.15, P = NS). At rest and during exercise, both with intact reflexes and after beta-adrenergic blockade, the ratio of Ees to Ea remained within the range in which SW is > 95% of maximum. We conclude that during exercise, beta-adrenergic stimulation shifts the LV Pes-Ves relation to the left with an increased slope. This more than offsets the increase in Ea.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
W C Little; C P Cheng
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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:  264     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1993 May 
Date Detail:
Created Date:  1993-06-21     Completed Date:  1993-06-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1629-33     Citation Subset:  IM    
Affiliation:
Section of Cardiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157-1045.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / pharmacology
Animals
Arteries
Blood Pressure*
Blood Volume*
Coronary Vessels / physiology*
Dogs
Hemodynamics / drug effects
Metoprolol / pharmacology
Physical Exertion*
Ventricular Function, Left*
Grant Support
ID/Acronym/Agency:
HL-37324/HL/NHLBI NIH HHS; HL-42364/HL/NHLBI NIH HHS; HL-45258/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 37350-58-6/Metoprolol

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


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