Document Detail


Myocardial failure with altered response to adrenaline in endotoxin shock.
MedLine Citation:
PMID:  1097013     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1 There is a growing concensus that myocardial performance in the early stages of experimental endotoxic and septic shock is relatively normal; however, recent reports have identified an intermediate phase of shock when myocardial dysfunction is clearly apparent.2 The mechanism of dysfunction has become a subject of intense investigation. A current view is that altered myocardial responsiveness to circulating catecholamines may play an important role in the dysfunction observed after endotoxin administration. The present studies, in which an isolated working heart preparation of the dog was used, were designed to test this hypothesis. This particular experimental preparation was selected to provide an adequate interpretation of results; cardiac output, afterload, and concentrations of adrenaline reaching the coronary vascular bed were controlled in all experiments. Responses to infusions of adrenaline were recorded in the ;steady-state' condition. Control (non-shocked) heart responses to adrenaline were highly reproducible in terms of inotropic, chronotropic and coronary vascular behaviour.3 Results from the study document myocardial dysfunction within 4-6 h following an LD(70) endotoxin administration on the basis of increased left ventricular end diastolic pressure (LVEDP), decreased cardiac power and myocardial efficiency, and depressed negative and positive dP/dt parameters.4 Findings suggest significantly altered responsiveness of the myocardium to infused adrenaline at rates of 1, 2, and 5 mug/min with concentrations between 10 and 1 ng/ml blood. LVEDP was elevated while calculated power and efficiency parameters remained significantly below control values during infusion of adrenaline in endotoxin-treated hearts. Depressions of responsiveness were interpreted to occur on the basis of failure to restore positive and negative dP/dt to normal values and depressed coronary blood flow responses during adrenaline administration. Increases in coronary flow were regularly less in experimental hearts than the controls. Heart rate responses to adrenaline in both failing and non-failing hearts were identical.5 In conclusion, it is suggested that myocardial contractile and relaxation characteristics and coronary vascular responses to adrenaline infusion are depressed in endotoxin shock during the period of demonstrated myocardial dysfunction. No distinct causal relationships were observed between the altered myocardial responsiveness and pathogenesis of heart dysfunction since myocardial dysfunction and altered responsiveness to adrenaline were generally observed together. Myocardial oedema formation after endotoxin as previously reported by this laboratory may bear a relationship to the depressed negative dP/dt response to adrenaline.
Authors:
L T Archer; M R Black
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  British journal of pharmacology     Volume:  54     ISSN:  0007-1188     ISO Abbreviation:  Br. J. Pharmacol.     Publication Date:  1975 Jun 
Date Detail:
Created Date:  1975-10-30     Completed Date:  1975-10-30     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7502536     Medline TA:  Br J Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  145-55     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Gas Analysis
Blood Pressure / drug effects
Dogs
Epinephrine / pharmacology*
Escherichia coli
Heart / drug effects*
Heart Failure / chemically induced,  etiology*
Myocardium / metabolism
Oxygen Consumption / drug effects
Shock, Septic / complications*
Time Factors
Chemical
Reg. No./Substance:
51-43-4/Epinephrine
Comments/Corrections

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