Ablation at the Coronary Sinus Diverticular Neck for a Posteroseptal Accessory Pathway With Coronary Sinus Ostial Atresia.

After failed annular ablation for a posteroseptal accessory pathway with coronary sinus ostial atresia, direct coronary sinus angiography delineated a coronary sinus diverticulum with left atrial drainage. Targeted mapping localized the effective ablation site to the diverticular neck, where radiofrequency delivery eliminated accessory pathway conduction.