Repeated dual external direct cardioversions using two simultaneous 360-J shocks for refractory atrial fibrillation are safe and effective.

Failure of cardioversion of atrial fibrillation (AF) to sinus rhythm (SR) by standard external direct current cardioversion (DCC) may be due to failure of delivery of enough defibrillating energy rather than to the true refractoriness of AF. Ninety-nine patients with persistent AF (76 male; age 63.7 +/- 0.4 years; weight 113.1 +/- 25.1 kg) who failed standard DCC were included in this report. Under anesthesia, QRS synchronous shocks were delivered across anteroposterior electrodes in the following sequence: (1) a single 360-J shock; (2) another single 360-J shock within 2 minutes; (3) 30 minutes of rest, reinduction of anesthesia and delivery of two simultaneous monophasic 360-J shocks. All patients underwent all three DCC steps. Sixty-six (67%) patients converted to SR following the first dual simultaneous shock. Fourteen patients (14%) required more than one dual shock to achieve SR. This increased the overall success rate of resuming SR to 81%. Except for minor skin burns in three patients there were no procedure related complications. On follow-up at 1 month, 55 (56%) patients were still in SR, whereas 50 (51%) patients maintained SR at 12 months. This was similar to our general DCC population (55% of the 1698 patients were in SR 6 months post-DCC, P = ns). In conclusion, dual external monophasic 360-J DCC is an effective rescue technique for restoration of SR in patients with AF refractory to standard DCC. AF in these patients seems to be as amenable to chronic suppression as AF in the general population of DCC patients.