Document Detail


Mechanisms of ventricular fibrillation induction by 60-Hz alternating current in isolated swine right ventricle.
MedLine Citation:
PMID:  11004149     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: The mechanisms by which 60-Hz alternating current (AC) can induce ventricular fibrillation (VF) are unknown. METHODS AND RESULTS: We studied 7 isolated perfused swine right ventricles in vitro. The action potential duration restitution curve was determined. Optical mapping techniques were used to determine the patterns of activation on the epicardium during 5-second 60-Hz AC stimulation (10 to 999 microA). AC captured the right ventricles at 100+/-65 microA, which is significantly lower than the direct current pacing threshold (0.77+/-0.45 mA, P:<0.05). AC induced ventricular tachycardia or VF at 477+/-266 microA, when the stimulated responses to AC had (1) short activation CLs (128+/-14 ms), (2) short diastolic intervals (16+/-9 ms), and (3) short diastolic intervals associated with a steep action potential duration restitution curve. Optical mapping studies showed that during rapid ventricular stimulation by AC, a wave front might encounter the refractory tail of an earlier wave front, resulting in the formation of a wave break and VF. Computer simulations reproduced these results. CONCLUSIONS: AC at strengths less than the regular pacing threshold can capture the ventricle at fast rates. Accidental AC leak to the ventricles could precipitate VF and sudden death if AC results in a fast ventricular rate coupled with a steep restitution curve and a nonuniform recovery of excitability of the myocardium.
Authors:
O Voroshilovsky; Z Qu; M H Lee; T Ohara; G A Fishbein; H L Huang; C D Swerdlow; S F Lin; A Garfinkel; J N Weiss; H S Karagueuzian; P S Chen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  102     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2000 Sep 
Date Detail:
Created Date:  2000-09-29     Completed Date:  2001-02-22     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1569-74     Citation Subset:  IM    
Affiliation:
Division of Cardiology, Department of Medicine, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA 90048, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Electricity / adverse effects*
Heart Ventricles / physiopathology
Swine
Time Factors
Ventricular Fibrillation / etiology*,  physiopathology
Grant Support
ID/Acronym/Agency:
HL-44880/HL/NHLBI NIH HHS; HL-58533/HL/NHLBI NIH HHS; P50-HL-52319/HL/NHLBI NIH HHS

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


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