Document Detail


Safety of transvenous low energy cardioversion of atrial fibrillation in patients with a history of ventricular tachycardia: effects of rate and repolarization time on proarrhythmic risk.
MedLine Citation:
PMID:  9507545     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The objective of this study was to assess the safety and efficacy of transvenous low energy cardioversion of atrial fibrillation in patients with ventricular tachycardia and atrial fibrillation and to study the mechanisms of proarrhythmia. Previous studies have demonstrated that cardioversion of atrial fibrillation using low energy, R wave synchronized, direct current shocks applied between catheters in the coronary sinus and right atrium is feasible. However, few data are available regarding the risk of ventricular proarrhythmia posed by internal atrial defibrillation shocks among patients with ventricular arrhythmias or structural heart disease. Atrial defibrillation was performed on 32 patients with monomorphic ventricular tachycardia and left ventricular dysfunction. Shocks were administered during atrial fibrillation (baseline shocks), isoproterenol infusion, ventricular pacing, ventricular tachycardia, and atrial pacing. Baseline shocks were also administered to 29 patients with a history of atrial fibrillation but no ventricular arrhythmias. A total of 932 baseline shocks were administered. No ventricular proarrhythmia was observed after well-synchronized baseline shocks, although rare inductions of ventricular fibrillation occurred after inappropriate T wave sensing. Shocks administered during wide-complex rhythms (ventricular pacing or ventricular tachycardia) frequently induced ventricular arrhythmias, but shocks administered during atrial pacing at identical ventricular rates did not cause proarrhythmia. The risk of ventricular proarrhythmia after well-synchronized atrial defibrillation shocks administered during narrow-complex rhythms is low, even in patients with a history of ventricular tachycardia. The mechanism of proarrhythmia during wide-complex rhythms appears not to be related to ventricular rate per se, but rather to the temporal relationship between shock delivery and the repolarization time of the previous QRS complex.
Authors:
G R Simons; K H Newby; M M Kearney; M J Brandon; A Natale
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Pacing and clinical electrophysiology : PACE     Volume:  21     ISSN:  0147-8389     ISO Abbreviation:  Pacing Clin Electrophysiol     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-06-11     Completed Date:  1998-06-11     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  7803944     Medline TA:  Pacing Clin Electrophysiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  430-7     Citation Subset:  IM    
Affiliation:
Department of Medicine, Duke University Medical Center, North Carolina, USA.
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MeSH Terms
Descriptor/Qualifier:
Aged
Atrial Fibrillation / complications*,  therapy*
Cardiac Pacing, Artificial
Chi-Square Distribution
Electric Countershock / adverse effects,  methods*
Electrophysiology
Female
Heart Rate
Humans
Male
Middle Aged
Tachycardia, Ventricular / complications*
Ventricular Fibrillation / etiology

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


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