Atrial fibrillation (AF) has been treated with DC shocks delivered transthoracically, but in 5-30% of patients, the procedures fail to restore sinus rhythm (SR). We hypothesized that applying high energy shock waves to the chest may overcome the inadequate penetration of electrical shock to the atrium. The aim of this study was to evaluate the efficacy of higher energy external DC shock for the treatment of refractory AF coexisting with cardiovascular disease using a synchronized double external defibrillator.
Fifteen patients (mean age 65 ± 8) with refractory AF to standard DC cardioversion (CV) underwent higher energy DC shock using a double external defibrillator. Concomitant heart disease was present in all patients. Warfarin and amiodarone (600 mg/day), were administered for at least three weeks duration before DC CV. Sedation was performed with IV midazolam. Two defibrillator paddles were positioned on the anterior and posterior chest wall in a right lateral decubitus position. Defibrillators were synchronized to the R waves and simultaneously 720 joules of energy was administered to the patients. Amiodarone (200 mg/day) was continuously administered after DC shock to maintain SR.
Sinus rhythm was obtained in 13 patients. Sinus rhythm was persistent in 11 patients for six months duration. Creatine kinase MB fractions were normal at 4 (22 ± 4 IU/L) and 12 hours (18 ± 4 IU/L). None of the patients developed significant hemodynamic compromise or congestive heart failure, higher AV block, stroke, or transient ischemic cerebral events.
The results indicate that higher energy DC shock application using a double external defibrillator is an effective and safe method for the cardioversion of refractory AF. We believe this procedure should be performed before internal atrial cardioversion.