Document Detail


Vulnerability to re-entry in simulated two-dimensional cardiac tissue: effects of electrical restitution and stimulation sequence.
MedLine Citation:
PMID:  18163779     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution properties affect the initiation of re-entry by premature extrastimuli in two-dimensional cardiac tissue models. We studied two pacing protocols for inducing re-entry following the "sinus" rhythm (S1) beat: (1) a single premature (S2) extrastimulus in heterogeneous tissue; (2) two premature extrastimuli (S2 and S3) in homogeneous tissue. In the first case, the vulnerable window of re-entry is determined by the spatial dimension and extent of the heterogeneity, and is also affected by electrical restitution properties and the location of the premature stimulus. The vulnerable window first increases as the action potential duration (APD) difference between the inside and outside of the heterogeneous region increases, but then decreases as this difference increases further. Steeper APD restitution reduces the vulnerable window of re-entry. In the second case, electrical restitution plays an essential role. When APD restitution is flat, no re-entry can be induced. When APD restitution is steep, re-entry can be induced by an S3 over a range of S1S2 intervals, which is also affected by conduction velocity restitution. When APD restitution is even steeper, the vulnerable window is reduced due to collision of the spiral tips.
Authors:
Diana X Tran; Ming-Jim Yang; James N Weiss; Alan Garfinkel; Zhilin Qu
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Chaos (Woodbury, N.Y.)     Volume:  17     ISSN:  1054-1500     ISO Abbreviation:  Chaos     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-12-31     Completed Date:  2008-04-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100971574     Medline TA:  Chaos     Country:  United States    
Other Details:
Languages:  eng     Pagination:  043115     Citation Subset:  IM    
Affiliation:
Cardiovascular Research Laboratories, Department of Physiological Science, David Geffen School of Medicine at UCLA, University of California, Los Angeles, California 90095, USA.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials
Animals
Arrhythmias, Cardiac / pathology
Computer Simulation
Electrophysiology*
Endocardium / pathology
Humans
Models, Cardiovascular
Models, Theoretical
Myocardium / pathology*
Nonlinear Dynamics
Pericardium / pathology
Systole
Grant Support
ID/Acronym/Agency:
P01 HL078931/HL/NHLBI NIH HHS

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


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