Document Detail


Diastolic viscous properties of the intact canine left ventricle.
MedLine Citation:
PMID:  2376076     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The viscoelastic model of the ventricle predicts that the rate of change of volume (strain rate) is a determinant of the instantaneous pressure in the ventricle during diastole. Because relaxation is not complete before the onset of filling, one cannot distinguish the individual effects of relaxation and viscosity unless the passive and active components that determine the ventricular pressure are separated. To overcome this problem, we used the method of ventricular volume clamping to compare the pressures in the fully relaxed ventricle at a given volume at zero strain rate (static pressure) and high strain rate (dynamic pressure). Six open-chest, fentanyl-anesthetized dogs were instrumented with micromanometers and an electronically controlled mitral valve occluder in series with the electromagnetic flow probe. We reasoned as follows: If there were significant viscosity, then the dynamic pressure would be higher than the static pressure. The static pressure was measured when the ventricle was completely relaxed following a mitral valve occlusion after an arbitrary filling volume had been achieved. The dynamic pressure was determined by delaying the onset of filling until relaxation was complete and then measuring the pressure at the same volume that was achieved when the static pressure was measured. In 19 different hemodynamic situations, the dynamic and static pressures were identical (mean difference, 0.1 +/- 0.8 mm Hg), indicating that in the passive ventricle viscoelastic effects are insignificant and do not contribute to the left ventricular diastolic pressure under normal filling rates.
Authors:
S D Nikolic; K Tamura; T Tamura; M Dahm; R W Frater; E L Yellin
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  67     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1990 Aug 
Date Detail:
Created Date:  1990-09-06     Completed Date:  1990-09-06     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  352-9     Citation Subset:  IM    
Affiliation:
Department of Cardiothoracic Surgery, Albert Einstein College of Medicine, Bronx, NY 10461.
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MeSH Terms
Descriptor/Qualifier:
Animals
Diastole*
Dogs
Elasticity
Heart / physiology*
Mitral Valve / physiology
Models, Biological
Muscle Relaxation
Muscle, Smooth / physiology
Myocardial Contraction*
Pressure
Ventricular Function
Viscosity
Grant Support
ID/Acronym/Agency:
P01 HL-37412/HL/NHLBI NIH HHS

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


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