[Internal defibrillation for cardioversion of atrial fibrillation during radiofrequency catheter ablation in a patient with WPW syndrome].

Although radiofrequency catheter ablation of accessory pathways during atrial fibrillation is possible (1), localisation of bypass tracts and delivery of radiofrequency current may be easier and safer in sinus rhythm. We report on a patient who developed atrial fibrillation with a fast ventricular response during mapping of a right posteroseptal atrioventricular pathway; after internal atrial defibrillation a successful radiofrequency ablation of the accessory pathway could be performed.Having venous sheaths already in place during electrophysiological studies, internal atrial cardioversion is a fast and uncomplicated procedure which may be the treatment of choice in case induced atrial fibrillation does not resolve spontaneously.