We report a case of a malignant right free wall AP that showed very rapid conduction during atrial fibrillation. The accessory pathway was attached to from the right atrial appendage to the right ventricle. Catheter ablation from an endocardial approach was met with limited success. Epicardial mapping of the atrial insertion site was achieved via a subxiphoid pericardial puncture. Long-term success was noted after ablation was performed in the epicardial space at the site of the tightest VA interval.
Keywords: Wolff-Parkinson-White syndrome; catheter ablation; supraventricular tachycardia.