Document Detail


Origin of initial escape beat during graded vagal stimulation.
MedLine Citation:
PMID:  1110335     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Graded vagal stimulation was applied to the distal vago-sympathetic trunk in anesthetized dogs. The effects of vagal stimulation were expressed as cardiac delay time, which is specifically measured as the R-R interval of the asystolic period or bradycardial beat, minus the control R-R interval. Graded vagal effects were best obtained by stimulation with varying pulse duration at fixed voltage and frequency. As pulse duration was increased, progressive bradycardia and brief cardiac arrest occurred. With further increase in pulse duration, cardiac delay time increased markedly and remained essentially unchanged over a wide range of still greater pulse durations. ECG's recorded stimultaneously showed initial sinus bradycardia, atrial pacemakers and A-V junctional beats during brief cardiac delays. The initial escape beat following prolonged cardiac delay was always A-V junctional or ventricular ectopic in origin. It is concluded that the initial escape beat following prolonged cardiac delay arises from latent ventricular pacemakers not subject to vagal influence.
Authors:
C N Peiss; H A Spurgeon
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of electrocardiology     Volume:  8     ISSN:  0022-0736     ISO Abbreviation:  J Electrocardiol     Publication Date:  1975 Jan 
Date Detail:
Created Date:  1975-04-14     Completed Date:  1975-04-14     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0153605     Medline TA:  J Electrocardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  25-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Atrioventricular Node / physiology*
Bradycardia / physiopathology
Bundle of His / physiology
Dogs
Electrocardiography
Heart Arrest, Induced
Heart Conduction System / drug effects,  physiology*
Heart Rate*
Heart Ventricles / innervation*
Propranolol / pharmacology
Pulse
Purkinje Fibers / physiology
Sinoatrial Node / drug effects
Vagus Nerve / physiology*
Chemical
Reg. No./Substance:
525-66-6/Propranolol

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


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