| Multiple monophasic shocks improve electrotherapy of ventricular tachycardia in a rabbit model of chronic infarction. | |
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MedLine Citation:
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PMID: 19560090 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: We previously showed that the cardioversion threshold (CVT) for ventricular tachycardia (VT) is phase dependent when a single monophasic shock (1MP) is used. OBJECTIVE: The purpose of this study was to extend these findings to a biphasic shock (1BP) and to compare the efficacy of phase-independent multiple monophasic (5MP) and biphasic shocks (5BP). METHODS: Panoramic optical mapping with blebbistatin (5 microM) was performed in postmyocardial infarction rabbit hearts (n = 8). Flecainide (1.64 +/- 0.68 microM) was administered to promote sustained arrhythmias. 5MP and 5BP were applied within one VT cycle length (CL). Results were compared to 1BP and antitachycardia pacing. RESULTS: We observed monomorphic VT with CL = 149.6 +/- 18.0 ms. Similar to 1MP, CVTs of 1BP were found to be phase dependent, and the maximum versus minimum CVT was 8.6 +/- 1.7 V/cm versus 3.7 +/- 1.9 V/cm, respectively (P = .0013). Efficacy of 5MP was higher than that of 1BP and 5BP. CVT was 3.2 +/- 1.4 V/cm for 5MP versus 5.3 +/- 1.9 V/cm for 5BP (P = .00027). 5MP versus averaged 1BP CVT was 3.6 +/- 2.1 V/cm versus. 6.8 +/- 1.5 V/cm, respectively (P = .00024). Antitachycardia pacing was found to be completely ineffective in this model. CONCLUSION: Maintenance of shock-induced virtual electrode polarization by multiple monophasic shocks over a VT cycle is responsible for unpinning of reentry leading to self-termination. Elimination of virtual electrode polarization by shock polarity reversal during multiple biphasic shocks proved ineffective. A significant reduction in CVT can be achieved by applying multiple monophasic shocks within one VT CL or one single shock at the proper coupling interval. |
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Authors:
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Wenwen Li; Crystal M Ripplinger; Qing Lou; Igor R Efimov |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, N.I.H., Extramural Date: 2009-03-11 |
Journal Detail:
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Title: Heart rhythm : the official journal of the Heart Rhythm Society Volume: 6 ISSN: 1556-3871 ISO Abbreviation: Heart Rhythm Publication Date: 2009 Jul |
Date Detail:
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Created Date: 2009-06-29 Completed Date: 2009-09-30 Revised Date: 2011-04-26 |
Medline Journal Info:
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Nlm Unique ID: 101200317 Medline TA: Heart Rhythm Country: United States |
Other Details:
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Languages: eng Pagination: 1020-7 Citation Subset: IM |
Affiliation:
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Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Disease Models, Animal Electric Countershock / methods* Female Male Myocardial Infarction / complications*, physiopathology Rabbits Tachycardia, Ventricular / etiology, physiopathology, therapy* |
| Grant Support | |
ID/Acronym/Agency:
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R01 HL059464-02/HL/NHLBI NIH HHS; R01 HL059464-03/HL/NHLBI NIH HHS; R01 HL067322-06/HL/NHLBI NIH HHS; R01 HL067322-07/HL/NHLBI NIH HHS; R01HL-067322/HL/NHLBI NIH HHS |
| Comments/Corrections | |
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