Document Detail

Inotropic responsiveness of the heart in catecholamine cardiomyopathy.
MedLine Citation:
PMID:  7457336     Owner:  NLM     Status:  MEDLINE    
Inotropic responsiveness to norepinephrine (NE) or Ca2+ was studied in 15 rabbits with catecholamine cardiomyopathy (CM) and the results were compared with 11 controls. The former group was prepared by infusing NE (2 micrograms/min/kg) for 90 minutes, 2 to 3 days prior to study, and injury was confirmed and quantified histologically. Comparison of NE dose-response curves relating percent increase of left ventricular (LV) dP/dt max to NE dose in six controls and 10 CM hearts revealed significant depression of CM contractility. Responses to graded infusions of Ca2+ were also determined in five controls and in five CM animals. With the increases in serum Ca2+ identical in the two groups, the percent increases in dP/dt max were less in CM hearts. Further, NE dose-response curves obtained during continuous CaCl2 infusion were sharply attenuated in CM hearts and initial LV end-diastolic pressure (LVEDP) in the CM hearts was considerably higher than in the controls. It is concluded that inotropic sensitivity to NE is reduced in CM hearts. This cannot be ascribed to altered beta-receptors alone, because responsiveness to Ca2+ was also reduced. Myocardial damage was indicated by histology and elevated LVEDP. Moreover, the normalized percent data suggest tht the remaining viable fibers in the CM hearts were functioning subnormally and thus reduced performance was not due solely to the decreased number of contracting units.
R R Fripp; J C Lee; S E Downing
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American heart journal     Volume:  101     ISSN:  0002-8703     ISO Abbreviation:  Am. Heart J.     Publication Date:  1981 Jan 
Date Detail:
Created Date:  1981-03-17     Completed Date:  1981-03-17     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370465     Medline TA:  Am Heart J     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  17-21     Citation Subset:  AIM; IM    
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MeSH Terms
Blood Pressure / drug effects
Calcium / blood
Cardiomyopathies / chemically induced*
Dose-Response Relationship, Drug
Heart Rate / drug effects
Heart Ventricles / drug effects,  pathology
Myocardial Contraction / drug effects*
Norepinephrine / pharmacology
Grant Support
Reg. No./Substance:
0/Catecholamines; 51-41-2/Norepinephrine; 7440-70-2/Calcium

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

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