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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
Author(s) -
SIMONS GRANT R.,
NEWBY KEITH H.,
KEARNEY MARGARET M.,
BRANDON MARY J.,
NATALE ANDREA
Publication year - 1998
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1998.tb00068.x
Subject(s) - medicine , cardiology , cardioversion , atrial fibrillation , ventricular tachycardia , tachycardia , atrial tachycardia , catheter ablation
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 ofproarrhythmia. 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 (ventricularpacing 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.