Document Detail

Interactions between extracellular stimuli and excitation waves in an atrial reentrant loop.
MedLine Citation:
PMID:  14521659     Owner:  NLM     Status:  MEDLINE    
Extracellular Stimuli in an Atrial Reentrant Loop. INTRODUCTION: The interactions between extracellular stimuli and excitation waves propagating in a reentrant loop are a complex function of stimulus parameters, structural properties, membrane state, and timing. Here the goal was a comprehensive understanding of the mechanisms and frequencies of the major interactions between the advancing excitation wave and a single extracellular stimulus, separated from issues of anatomic or geometric complexity. METHODS AND RESULTS: A modernized computer model of a thin ring of uniform tissue that included a pair of extracellular stimulus electrodes (anode/cathode) was used to model one-dimensional cardiac reentry. Questions and results included the following: (1) What are the major interactions between a stimulus and the reentrant propagation wave, and are they induced near the cathode or near the anode; and, for each interaction, what are the initiating amplitude range and timing interval? At the cathode, the well-known mechanism of retrograde excitation terminated reentry; changes in timing or amplitude produced double-wave reentry or phase reset. At the anode, termination occurred at different cells depending on stimulus amplitude. (2) Relatively how often did termination occur at the anode? For most stimulus amplitudes, termination occurred more often at the anode than at the cathode, although not always at the same cell. (3) With random timing, what is the probability of terminating reentry? Stimulation for 5 msec terminated reentry with a probability from 0% to approximately 10%, as a function of increasing stimulus amplitude. CONCLUSION: A single extracellular stimulus can initiate major changes in reentrant excitation via multiple mechanisms, even in a simple geometry. Termination of reentry, phase shifts, or double-wave reentry each occurs over well-defined ranges of stimulus amplitude and timing.
Chad R Johnson; Roger C Barr
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  14     ISSN:  1045-3873     ISO Abbreviation:  J. Cardiovasc. Electrophysiol.     Publication Date:  2003 Oct 
Date Detail:
Created Date:  2003-10-02     Completed Date:  2004-04-13     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1064-74     Citation Subset:  IM    
Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.
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MeSH Terms
Action Potentials
Atrial Fibrillation / physiopathology,  therapy
Cardiac Pacing, Artificial / methods*
Computer Simulation
Electric Stimulation
Extracellular Space*
Heart Atria / physiopathology*
Heart Conduction System / physiopathology*
Models, Cardiovascular*
Models, Neurological*
Myocytes, Cardiac
Tachycardia, Atrioventricular Nodal Reentry / physiopathology*,  therapy*
Grant Support
Comment In:
J Cardiovasc Electrophysiol. 2003 Oct;14(10):1075-6   [PMID:  14521660 ]

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

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