Document Detail

Atrial activation occurring immediately after successful cardioversion of atrial fibrillation.
MedLine Citation:
PMID:  18181915     Owner:  NLM     Status:  MEDLINE    
BACKGROUND AND OBJECTIVE: Electrical defibrillation is very effective in interrupting atrial fibrillation (AF). However, its mechanism is not completely understood. We report our observations in patients subjected to external electriocardioversion (ECV) of atrial fibrillation and contrast them with recent theories about defibrillation mechanism. METHODS: In 13 consecutive patients transthoracic electrical cardioversion for AF was performed during an electrophysiological study (11 monophasic -200-360 J- and 9 biphasic shocks -50-150 J-). About 10-16 electrograms were obtained with multipolar catheters recording right atrium, coronary sinus, and right pulmonary artery. AF was defined by interelectrogram intervals and changing sequences among recordings, indicating complete lack of organization. We evaluated the presence of propagated activations immediately (<300 ms) after successful shocks (>or=1 discrete electrogram in all recordings). In unsuccessful shocks we evaluated changes in electrogram morphology (discrete/fragmented) and interelectrogram intervals before and after defibrillation. RESULTS: About 16/20 shocks terminated AF. In 6/16 one or two cycles of atrial activation were recorded just after the shock and before AF ended. In 10/16 AF was interrupted immediately after the shock. 4/20 shocks did not interrupt the arrhythmia. After these shocks, transient organization of recorded activity with longer interelectrogram cycle length and disappearance of fragmented activity were transiently observed. CONCLUSION: Our clinical findings in atrial defibrillation in vivo reproduce experimental data that show myocardial activations early after successful direct current shocks. These observations suggest that successful defibrillation depends not only on the immediate effects of the shock, but also on transient effects on electrophysiological properties of the myocardium, capable of interrupting persistent or reinitiated activations.
Arturo Martín Peñato Molina; Francisco G Cosío; Agustín Pastor; Ambrosio Núñez; Paula Awamleh
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  31     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  2008 Jan 
Date Detail:
Created Date:  2008-01-09     Completed Date:  2008-05-13     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  88-92     Citation Subset:  IM    
Servicio de Cardiología, Complejo Hospitalario Torrecardenas, Almería, Spain.
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MeSH Terms
Atrial Fibrillation / physiopathology*,  therapy*
Chi-Square Distribution
Electric Countershock*
Heart Atria / physiopathology*
Middle Aged
Treatment Outcome

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

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