Document Detail


Electrical restitution in the endocardium of the intact human right ventricle.
MedLine Citation:
PMID:  1739524     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To characterise electrical restitution in the intact human heart. PATIENTS AND METHODS: A series of monophasic action potential electrical restitution curves were constructed from a single right ventricular endocardial site in eight patients (three men) without structural heart disease aged 52-68 (mean 55 years). A combination pacing/monophasic action potential electrode was used to pace and record monophasic action potentials at drive cycle lengths of from 350 ms to 1500 ms. Ventricular extrastimuli were delivered at 20 cycle intervals and decreased from the longest coupling interval attainable without escape beats. RESULTS: Restitution curves shifted downward and towards the left; steady state action potential duration shifted from the restitution plateau and descended the curve, the amount of shift being linearly related to drive cycle length in two patients in whom the relation could be assessed; the amount of monophasic action potential shortening was a function of the degree of prematurity and that relation was unaffected by drive rate; the magnitude of restitution and the time constant of the restitution curve were not changed significantly by altered drive cycle length. CONCLUSION: In the intact heart in vivo, electrical restitution (of the monophasic action potential) has similar characteristics to those (of the transmembrane action potential) in cellular preparations in vitro. Thus the alteration of action potential plateau currents by instantaneous rate change or drug effects, which can be directly observed by techniques available to the cellular electrophysiologist, may be indirectly assessed in vivo by characterisation of the effect of these on electrical restitution.
Authors:
J M Morgan; D Cunningham; E Rowland
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  British heart journal     Volume:  67     ISSN:  0007-0769     ISO Abbreviation:  Br Heart J     Publication Date:  1992 Jan 
Date Detail:
Created Date:  1992-03-25     Completed Date:  1992-03-25     Revised Date:  2010-03-24    
Medline Journal Info:
Nlm Unique ID:  0370634     Medline TA:  Br Heart J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  42-6     Citation Subset:  AIM; IM    
Affiliation:
Royal Brompton National Heart and Lung Hospital, London.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology
Aged
Electric Stimulation
Electrocardiography
Endocardium / physiology*
Female
Humans
Male
Middle Aged
Ventricular Function
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