Document Detail

Autonomic response to coronary occlusion in animals susceptible to ventricular fibrillation.
MedLine Citation:
PMID:  2603974     Owner:  NLM     Status:  MEDLINE    
Disturbances in autonomic control during myocardial ischemia may contribute significantly to the development of malignant cardiac arrhythmias. Therefore acute ischemia was induced in 29 mongrel dogs with healed myocardial infarctions during an exercise test. Seventeen animals developed ventricular fibrillation (susceptible, S), whereas 12 dogs did not (resistant, R). Before the exercise plus ischemia test a coronary occlusion was made at rest. The amplitude of respiratory sinus arrhythmia (0.24- to 1.04-Hz component of R-R interval fluctuation) was used as an index of cardiac vagal tone. Acute ischemia elicited a significantly larger heart rate increase in susceptible animals (S: control 115.6 +/- 0.8, occlusion 176.4 +/- 8.2 beats/min vs. R: control 114.6 +/- 8.9, occlusion 145.7 +/- 7.5 beats/min). Accompanying the heart rate increase were significantly greater reductions in the cardiac vagal tone index in the susceptible animals. (S: control 6.4 +/- 0.3, occlusion 2.2 +/- 0.6 ln ms2 vs. R: control 6.6 +/- 0.4, occlusion 5.1 +/- 0.5 ln ms2). beta-Adrenergic receptor blockade reduced the heart rate increases but exacerbated the reductions in the cardiac vagal tone index. These data suggest that coronary artery occlusion elicits a significantly greater increase in sympathetic activity coupled with a greater reduction in parasympathetic activity in animals subsequently shown to be susceptible to ventricular fibrillation.
M N Collins; G E Billman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  257     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1989 Dec 
Date Detail:
Created Date:  1990-02-02     Completed Date:  1990-02-02     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1886-94     Citation Subset:  IM    
Department of Physiology, Ohio State University, Columbus 43210.
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MeSH Terms
Autonomic Nervous System / physiopathology*
Blood Pressure / drug effects
Coronary Disease / etiology,  physiopathology*
Coronary Vessels / physiology
Death, Sudden
Disease Susceptibility
Heart / drug effects,  physiopathology
Heart Rate / drug effects
Isoproterenol / pharmacology
Myocardial Infarction / physiopathology
Physical Exertion
Propranolol / pharmacology
Vagus Nerve / physiology
Ventricular Fibrillation / physiopathology*
Grant Support
Reg. No./Substance:
525-66-6/Propranolol; 7683-59-2/Isoproterenol

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

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