Double external direct-current shocks for refractory atrial fibrillation.

Encouraged by preliminary data using double external direct-current (DC) shocks in patients with atrial fibrillation refractory to single external DC shocks, we undertook a prospective study of all patients with atrial fibrillation of > 1-month duration using a shock sequence with (1) 1 shock of 200 J anterior-posterior, (2) 1 shock of 360 J anterior-posterior, (3) 1 shock of 360 J apex-anterior, and (4) double shocks with configurations 2 and 3 delivered almost simultaneously by 2 defibrillators. The double shocks appeared to be safe and restored sinus rhythm in approximately 2 of 3 of patients in whom DC cardioversion failed with single shocks.