Document Detail

Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts.
MedLine Citation:
PMID:  21839044     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Moderate global cooling of myocardial tissue was shown to destabilize 2-dimensional (2-D) reentry and facilitate its termination.
OBJECTIVE: This study sought to test the hypothesis that regional cooling destabilizes rotors and facilitates termination of spontaneous and DC shock-induced subepicardial reentry in isolated, endocardially ablated rabbit hearts.
METHODS: Fluorescent action potential signals were recorded from 2-D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts. Regional cooling (by 5.9°C ± 1.3°C) was applied to the left ventricular anterior wall using a transparent cooling device (10 mm in diameter).
RESULTS: Regional cooling during constant stimulation (2.5 Hz) prolonged the action potential duration (by 36% ± 9%) and slightly reduced conduction velocity (by 4% ± 4%) in the cooled region. Ventricular tachycardias (VTs) induced during regional cooling terminated earlier than those without cooling (control): VTs lasting >30 seconds were reduced from 17 of 39 to 1 of 61. When regional cooling was applied during sustained VTs (>120 seconds), 16 of 33 (48%) sustained VTs self-terminated in 12.5 ± 5.1 seconds. VT termination was the result of rotor destabilization, which was characterized by unpinning, drift toward the periphery of the cooled region, and subsequent collision with boundaries. The DC shock intensity required for cardioversion of the sustained VTs decreased significantly by regional cooling (22.8 ± 4.1 V, n = 16, vs 40.5 ± 17.6 V, n = 21). The major mode of reentry termination by DC shocks was phase resetting in the absence of cooling, whereas it was unpinning in the presence of cooling.
CONCLUSION: Regional cooling facilitates termination of 2-D reentry through unpinning of rotors.
Masatoshi Yamazaki; Haruo Honjo; Takashi Ashihara; Masahide Harada; Ichiro Sakuma; Kazuo Nakazawa; Natalia Trayanova; Minoru Horie; Jérôme Kalifa; José Jalife; Kaichiro Kamiya; Itsuo Kodama
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-08-10
Journal Detail:
Title:  Heart rhythm : the official journal of the Heart Rhythm Society     Volume:  9     ISSN:  1556-3871     ISO Abbreviation:  Heart Rhythm     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2011-12-26     Completed Date:  2012-10-29     Revised Date:  2014-09-19    
Medline Journal Info:
Nlm Unique ID:  101200317     Medline TA:  Heart Rhythm     Country:  United States    
Other Details:
Languages:  eng     Pagination:  107-14     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.
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MeSH Terms
Action Potentials / physiology
Cardiac Pacing, Artificial / methods*
Cold Temperature
Heart / physiology*
Heart Conduction System / physiopathology*
Heart Ventricles / physiopathology*
Tachycardia, Ventricular / physiopathology*
Voltage-Sensitive Dye Imaging
Grant Support

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

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