Catheter ablation for Wolff-Parkinson-White syndrome with coronary sinus diverticulum in a 15-year-old boy

The left posterior and posteroseptal accessory pathways often have an epicardial accessory and are associated with coronary vein anomalies, such as diverticulum, fusiform, or bulbous enlargement. We report the case of a 15-year-old boy who suffered from palpitation due to Wolff-Parkinson-White syndrome with coronary sinus diverticulum. An electrophysiology study revealed a left posterior accessory pathway and orthodromic atrioventricular reciprocating tachycardia. After the transseptal puncture, we performed mapping around the mitral annulus during sinus rhythm. We could not detect typical atrioventricular fusion accompanied with accessory pathway potential and failed to ablate around the mitral annulus. We revealed typical accessory pathway potential in a coronary vein and successfully ablated. After ablation, a right atrium angiography showed a successful ablation site was just at the neck of coronary sinus diverticulum. It is important for a successful and safe ablation to evaluate coronary vein anomalies in patients with left posterior and posteroseptal accessory pathways.