Document Detail

Disparate electrophysiological alterations accompanying dysrhythmia due to coronary occlusion and reperfusion in the cat.
MedLine Citation:
PMID:  709759     Owner:  NLM     Status:  MEDLINE    
The electrophysiologic changes associated with dysrhythmias induced by coronary occlusion and by subsequent reperfusion were characterized with six complimentary approaches in chloralose-anesthetized cats (n = 57) with proximal occlusion of the left anterior descending (LAD) coronary artery. Occlusion led to reproducible ventricular dysrhythmia which abated in 35 minutes. The electrophysiologic effects of reperfusion initiated at this time could be studied. Simultaneous bipolar electrograms (epi-, myo- and endocardial) from ischemic and normal zones were analyzed by computer. Before the onset of the dysrhythmia induced by occlusion, conduction was markedly slowed, with dV/dt decreasing to 34% +/- 6% of control and conduction time (endo- to epicardial activation) prolonged to 328 +/- 77% of control. However, these values returned toward normal with reperfusion, even though it also consistently induced dysrhythmia. The idioventricular escape rate (determined by intense vagal stimulation) was 62 +/- 6 beats/min during the dysrhythmia induced by occlusion (equal to control), but increased during the reperfusion dysrhythmia to 188 +/- 12 beats/min. The occlusion dysrhythmia was exacerbated, but the reperfusion dysrhythmia was suppressed by rapid atrial pacing. The refractory period progressively shortened after occlusion and remained decreased during early reperfusion. Thus, increased conduction time through myocardial and epicardial regions, asynchronous depolarization and shortening of the refractory period accompanied dysrhythmia induced by occlusion. In contrast, the dysrhythmia induced by reperfusion was characterized by normal conduction time, through myocardial regions with continued significant epicardial delay, overdrive suppression, synchronous depolarization and a high idioventricular rate.
P A Penkoske; B E Sobel; P B Corr
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  58     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1978 Dec 
Date Detail:
Created Date:  1979-01-26     Completed Date:  1979-01-26     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1023-35     Citation Subset:  AIM; IM    
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MeSH Terms
Arrhythmias, Cardiac / etiology*,  physiopathology
Blood Pressure
Cardiac Pacing, Artificial
Coronary Circulation
Coronary Disease / complications*,  physiopathology
Electric Stimulation
Heart Conduction System / physiopathology*
Heart Rate
Time Factors
Vagus Nerve / physiology

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

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