Depressed inotropic response to increased preload in rabbit hearts with left-ventricular dysfunction induced by chronic myocardial infarction

Ng, G.A., Hicks, M.N., Cobbe, S.M. and Smith, G.L. (2002) Depressed inotropic response to increased preload in rabbit hearts with left-ventricular dysfunction induced by chronic myocardial infarction. Pflügers Archiv - European Journal of Physiology, 444(4), pp. 513-522. (doi:10.1007/s00424-002-0848-3)

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Abstract

Chronic (8 weeks) coronary artery ligation caused marked left-ventricular dysfunction (LVD) in rabbits. The positive inotropic effect observed in vivo with intraventricular injection of saline in sham-operated (control) animals was reversed in rabbits with LVD. In vitro, a step increase in filling pressure from 10 to 15 cmH(2)O caused an immediate increase, followed by a slow increase, in left-ventricular peak systolic pressure (LVPmax) and cardiac output (CO) over 5-7 min in sham-operated hearts. No significant slow positive inotropic effect was observed in hearts with LVD in response to a standard increase in filling pressure. Progressive increases in filling pressure increased (LVPmax) and CO to a maximum value at 20 cmH(2)O in control hearts. In the LVD group, progressive increases in filling pressure caused a negative inotropic response and reduced CO. Hearts from the LVD group were significantly dilated compared with control hearts but no significant changes in myocardial compliance were observed in beating or quiescent hearts. These studies reveal an impaired inotropic response to increased ventricular filling in LVD rabbit hearts; this defect included the depression of the slow inotropic response to an increased end-diastolic volume. These changes appear not to be accompanied by altered passive mechanical properties.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Smith, Professor Godfrey and Hicks, Dr Martin and Cobbe, Professor Stuart
Authors: Ng, G.A., Hicks, M.N., Cobbe, S.M., and Smith, G.L.
College/School:College of Medical Veterinary and Life Sciences
College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:Pflügers Archiv - European Journal of Physiology
Publisher:Springer-Verlag
ISSN:0031-6768
ISSN (Online):1432-2013
Published Online:27 April 2014

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