Document Detail

Importance of location and timing of electrical stimuli in terminating sustained functional reentry in isolated swine ventricular tissues: evidence in support of a small reentrant circuit.
MedLine Citation:
PMID:  9323098     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: In excitable chemical media, a spiral wave is formed by reentrant excitation around a core and normal propagation away from the core. Whether or not this applies to cardiac muscle is unknown. METHODS AND RESULTS: In six isolated swine ventricular slices, we induced sustained episodes of functional reentry with a stationary core. A train of stimuli applied away from the core (7- to 8-mm distance) and near the core (within 1.6 mm) terminated 5 of 24 and 14 of 17 episodes of reentry, respectively (P<.001). When the stimulus was applied away from the core, successful terminations occurred when the line connecting the stimulus and the core was along the myocardial fiber orientation and when the coupling interval was 54+/-11% of the reentrant cycle length. Stimulation near the core terminated reentry primarily by propagation of the stimulus-induced wave fronts that closed up the excitable gap. However, in two episodes, the application of a stimulus near the core changed the electrogram morphology in only four bipolar pairs. This was sufficient to cause abrupt termination of reentry. CONCLUSIONS: (1) A thin layer of activation near the core is responsible for the maintenance of functional reentry. (2) Access to the tissue near the core is essential for the termination of functional reentry by a point stimulus. (3) To terminate reentry with a stimulus away from the core, the stimulus must occur at certain critical coupling intervals, and the line connecting the stimulus and the core must be roughly parallel to the fiber orientation.
K Kamjoo; T Uchida; T Ikeda; M C Fishbein; A Garfinkel; J N Weiss; H S Karagueuzian; P S Chen
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation     Volume:  96     ISSN:  0009-7322     ISO Abbreviation:  Circulation     Publication Date:  1997 Sep 
Date Detail:
Created Date:  1997-10-22     Completed Date:  1997-10-22     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2048-60     Citation Subset:  AIM; IM    
Department of Medicine, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, Calif 90048, USA.
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MeSH Terms
Anti-Arrhythmia Agents / pharmacology
Benzopyrans / pharmacology
Electric Countershock*
Heart Conduction System / drug effects,  physiopathology*
Muscle Fibers, Skeletal / drug effects,  physiology
Pacemaker, Artificial*
Pyrroles / pharmacology
Tachycardia, Atrioventricular Nodal Reentry / drug therapy,  physiopathology*
Grant Support
Reg. No./Substance:
0/Anti-Arrhythmia Agents; 0/Benzopyrans; 0/Pyrroles; 94470-67-4/Cromakalim

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

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