Radiofrequency catheter ablation of an accessory pathway during preexcited atrial fibrillation.

Radiofrequency catheter ablation of accessory pathways can not routinely be performed during preexcited atrial fibrillation. However, atrial fibrillation occurs frequently in patients with Wolff-Parkinson-White syndrome during an electrophysiologic study, causing difficulty for both the patient and the operator. In this case report we present two cases with Wolff-Parkinson-White syndrome treated by catheter ablation during preexcited atrial fibrillation. The localizations of accessory pathways were left lateral in one case, and right posteroseptal in the other.