Atrial pacing for suppression of early reinitiation of atrial fibrillationafter successful internal cardioversion

Aims To evaluate the efficacy of atrial pacing in the suppression of early reinitiation of atrial fibrillation after successful internal cardioversion . Methods and Results The efficacy of atrial pacing in suppressing early rein itiation of atrial fibrillation was studied in 12 of 45 (29%) patients with early reinitiation of atrial fibrillation after successful cardioversion. These patients were randomized to undergo either repeated defibrillation al one or repeated defibrillation followed by high right atrial pacing at 500 ms in a crossover fashion. In patients with persistent early reinitiation o f atrial fibrillation despite atrial pacing at 500 ms and repeated defibril lation, atrial pacing at 300 ms was tested. Lastly, if early reinitiation o f atrial fibrillation persisted. administration of intravenous sotalol (1.5 mg . kg(-1)) was tested. Atrial pacing at 500 ms after defibrillation prev ented early reinitiation of atrial fibrillation in five of 12 (42%) patient s, and was significantly more effective than repeated defibrillation (0/9 p atients, 0%, P<0.05). During atrial pacing at 500 ms, the density of atrial premature depolarizations (APDs) was significantly decreased (2.4 +/- 2.4 APDs . min(-1) vs 16.4 +/- 9.8 APDs . min(-1), P<0.05) and the coupling int erval of atrial premature depolarization was significantly increased (420 /- 32 ms vs 398 +/- 19 ms, P<0.05) as compared to no pacing. In the remaini ng seven (58%) patients, atrial pacing at 500 ms failed to prevent early re initiation of atrial fibrillation, but significantly decreased the density of atrial premature depolarization (3.4 +/- 2.4 APDs . min(-1) vs 14.2 +/- 3.8 APDs . min(-1), P<0.05) and delayed the onset of early reinitiation of atrial fibrillation (33 +/- 17s vs 11 +/- 11 s, P<0.05). Atrial pacing at 3 00 ms decreased the coupling interval of atrial premature depolarization as compared to no pacing and during atrial pacing at 500 ms (P<0.05), but wit hout early reinitiation of atrial fibrillation suppression. Administration of intravenous sotalol was effective in preventing early reinitiation of at rial fibrillation in five of seven (71%) patients where pacing failed to su ppress early reinitiation of atrial fibrillation. Conclusion The results of this study suggest that atrial pacing can be usef ul when combined with transvenous defibrillation in patients with early rei nitiation of atrial fibrillation. (Eur Heart J 2000; 21: 1167-1176) (C) 200 0 The European Society of Cardiology.