A case of a posteroseptal accessory pathway localized in the neck of a coronary sinus diverticulum

The presence of a coronary sinus diverticulum along with a posteroseptal accessory pathway in its neck makes electrophysiologic studies and a successful ablation difficult. It is accompanied by increased ventricular conduction through the accessory pathway. A 21-year-old male patient presented with a complaint of paroxysmal tachycardia of a 10-year history, which lasted about 30 minutes following a sudden onset. It was unresponsive to treatment with a beta-blocker and propafenone. An electrocardiogram obtained in normal sinus rhythm showed positive delta wave activity in lead V1 while inferior leads were negative. An electrophysiologic study showed a posteroseptal accessory pathway in the neck of the diverticulum and a very rapid ventricular response during atrial fibrillation, suggesting Wolff-Parkinson-White syndrome. Ablation through the diverticulum was successful.