Nonsurgical transthoracic epicardial ablation for the treatment of a resistant posteroseptal accessory pathway.

A case of Wolff-Parkinson-White syndrome successfully treated by transcutaneous epicardial radiofrequency ablation is described in a patient with a posteroseptal accessory pathway who had failed prior attempts of conventional endocardial and coronary venous system approaches. Simultaneous endocardial and pericardial space mapping was performed and only ablation from the pericardial space was successful, suggesting an epicardial course of the accessory pathway.