Document Detail

Electrophysiological properties of the fibrillating atrium: implications for therapy.
MedLine Citation:
PMID:  9612655     Owner:  NLM     Status:  MEDLINE    
1. Atrial fibrillation (AF) is the most commonly occurring cardiac dysrhythmia and remains a challenge to medical therapy. Although the disorder has been recognized for over 100 years, surprisingly very little is understood about its pathophysiology. Over the past decade, a variety of experimental and animal models of AF have been developed and these have provided insights into the mechanism of AF. 2. The pathophysiology of AF is complex. Atrial fibrillation can be caused either by a single source of very rapid impulses or, in the majority of cases, by multiple random re-entering wavelets. The notion that AF may be initiated by a single rapid firing focus and the perpetuation of AF may be partly dependent on macro re-entry around the natural atrial orifices provides a new potential curative therapy for AF by radiofrequency ablation. 3. Shortening of atrial wavelength, either by slow atrial conduction velocities, short atrial refractory periods or both, seems to predispose to development of intra-atrial re-entry and, thus, AF. The functional mechanism by which anti-arrhythmic drugs terminate AF appears to be by prolonging the wavelength and decreasing the number of re-entry wavelets. These understandings are important for the future development of effective anti-arrhythmic agents against AF. 4. The presence of a short and variable excitable gap during AF may be potentially important for termination of AF by pacing. 5. New insights are being gained into the potential role and mechanism of electrical remodelling of the atrium due to AF. Repeated induction of AF by rapid atrial pacing leads to a shortening of atrial refractoriness with loss of rate adaptation, which favours the induction and maintenance of AF. These electrophysiological changes were assumed to occur during repeated AF and to facilitate the generation of multiple re-entrant wavelets. These data suggest that prompt restoration of sinus rhythm and new novel therapy that prevents or diminishes electrical remodelling may promote maintenance of sinus rhythm after successful cardioversion.
H F Tse; C P Lau
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  25     ISSN:  0305-1870     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  1998 May 
Date Detail:
Created Date:  1998-09-25     Completed Date:  1998-09-25     Revised Date:  2005-11-16    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  AUSTRALIA    
Other Details:
Languages:  eng     Pagination:  293-302     Citation Subset:  IM    
Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong.
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MeSH Terms
Anti-Arrhythmia Agents / therapeutic use*
Atrial Fibrillation / physiopathology*,  therapy
Cardiac Pacing, Artificial*
Electric Stimulation
Heart Conduction System / physiopathology*
Reg. No./Substance:
0/Anti-Arrhythmia Agents

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