| The role of transmural ventricular heterogeneities in cardiac vulnerability to electric shocks. | |
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MedLine Citation:
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PMID: 17915299 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Transmural electrophysiological heterogeneities have been shown to contribute to arrhythmia induction in the heart; however, their role in defibrillation failure has never been examined. The goal of this study is to investigate how transmural heterogeneities in ionic currents and gap-junctional coupling contribute to arrhythmia generation following defibrillation strength shocks. This study used a 3D anatomically realistic bidomain model of the rabbit ventricles. Transmural heterogeneity in ionic currents and reduced sub-epicardial intercellular coupling were incorporated based on experimental data. The ventricles were paced apically, and truncated-exponential monophasic shocks of varying strength and timing were applied via large external electrodes. Simulations demonstrate that inclusion of transmural heterogeneity in ionic currents results in an increase in vulnerability to shocks, reflected in the increased upper limit of vulnerability, ULV, and the enlarged vulnerable window, VW. These changes in vulnerability stem from increased post-shock dispersion in repolarisation as it increases the likelihood of establishment of re-entrant circuits. In contrast, reduced sub-epicardial coupling results in decrease in both ULV and VW. This decrease is caused by altered virtual electrode polarisation around the region of sub-epicardal uncoupling, and specifically, by the increase in (1) the amount of positively polarised myocardium at shock-end and (2) the spatial extent of post-shock wavefronts. |
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Authors:
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Thushka Maharaj; Robert Blake; Natalia Trayanova; David Gavaghan; Blanca Rodriguez |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Review Date: 2007-08-22 |
Journal Detail:
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Title: Progress in biophysics and molecular biology Volume: 96 ISSN: 0079-6107 ISO Abbreviation: Prog. Biophys. Mol. Biol. Publication Date: 2008 Jan-Apr |
Date Detail:
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Created Date: 2008-02-25 Completed Date: 2008-05-30 Revised Date: 2011-09-26 |
Medline Journal Info:
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Nlm Unique ID: 0401233 Medline TA: Prog Biophys Mol Biol Country: England |
Other Details:
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Languages: eng Pagination: 321-38 Citation Subset: IM |
Affiliation:
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Computing Laboratory, University of Oxford, Oxford, OX1 3PG, UK. Thushka.Maharaj@comlab.ox.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Action Potentials
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physiology Animals Electric Countershock* Heart Ventricles / physiopathology* Humans Models, Cardiovascular |
| Grant Support | |
ID/Acronym/Agency:
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HL063195/HL/NHLBI NIH HHS; R01 HL063195-08/HL/NHLBI NIH HHS; R01 HL082729-01A1/HL/NHLBI NIH HHS |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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