Successful ablation of anomalous posteroseptal accessory pathway associated to coronary sinus diverticulum

Coronary sinus diverticulum is a congenital anomaly that is found in 7-11% of patients carriers of posteroseptal accessory pathway. We report the case of a 40-year-old woman admitted into our service with an episode of atrial fibrillation with severe hemodynamic compromise. After successful electrical cardioversion, 12-lead electrocardiogram showed the presence of posteroseptal accessory pathway. After failed attempt of endocardial ablation by retrograde aortic access, a second approach was tried directly through the coronary sinus access. Venography revealed the presence of a large diverticulum near the ostium and the accessory pathway was ablated successfully in the neck of it, where electrogram with continuous electrical activity was recorded, presenting a potential expressing the myocardial extension within the coronary sinus.