Document Detail


Measurements of active myocardial tension under a wide range of physiological loading conditions.
MedLine Citation:
PMID:  9001940     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Active tension developed while cardiac muscle shortens has been studied extensively under afterloaded isotonic or isovelocity conditions. However, these are not true in vivo loading conditions. To obtain more physiological loading, we controlled sarcomere length to follow the time courses that we observed previously in a beating canine left ventricle. Sarcomere length was measured by laser diffraction in 12 rat cardiac trabeculae, superfused with Krebs-Henseleit solution (25 degrees C; [Ca] = 1.5 mM). Force was measured by a silicon strain gauge. Sarcomere length time courses were scaled slightly in time to account for temperature and species differences. We examined the relationships between active tension and sarcomere length under loading observed over a wide range of left ventricular preloads and afterloads, and at two sites. Under all loading conditions, active tension was not isotonic but declined steadily throughout the ejection period. While there were major differences in peak tension dependent on loading conditions and the incidence of 'pre-ejection' sarcomere shortening, these factors did not influence the relationship between sarcomere length and peak active tension. This study provides excellent illustrations of the potential differences in stress (1) within a ventricular wall, and (2) under different operating conditions. Moreover, it provides data for developing models of fiber contraction to be synthesized into a whole heart for predicting potential differences in stress at all sites and under all loading conditions.
Authors:
J M Guccione; G S Le Prell; P P de Tombe; W C Hunter
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of biomechanics     Volume:  30     ISSN:  0021-9290     ISO Abbreviation:  J Biomech     Publication Date:  1997 Feb 
Date Detail:
Created Date:  1997-04-03     Completed Date:  1997-04-03     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0157375     Medline TA:  J Biomech     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  189-92     Citation Subset:  IM; S    
Affiliation:
Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, Baltimore, MD 21205-2195, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Body Temperature
Cardiac Volume
Dogs
Female
Glucose
Heart / physiology*
Heart Ventricles / ultrastructure
Isotonic Contraction / physiology
Lasers
Male
Muscle Fibers, Skeletal / physiology,  ultrastructure
Myocardial Contraction / physiology*
Myocardium / ultrastructure
Organ Preservation Solutions
Pericardium / physiology
Rats
Rats, Sprague-Dawley
Sarcomeres / physiology,  ultrastructure
Species Specificity
Stress, Mechanical
Stroke Volume
Tromethamine
Ventricular Function
Ventricular Function, Left
Ventricular Pressure
Grant Support
ID/Acronym/Agency:
1F32-HL-08492/HL/NHLBI NIH HHS; HL-30552/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Krebs-Henseleit solution; 0/Organ Preservation Solutions; 50-99-7/Glucose; 77-86-1/Tromethamine

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


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