Restrictive interatrial communication in hypoplastic left heart syndrome after modified Fontan repair

The occurrence of pulmonary venous obstruction after total cavopulmonary connection with intraatrial lateral tunnel is a rare occurrence. We present two cases of hypoplastic left heart syndrome with restrictive interatrial communication presenting late after this type of modified Fontan repair. This occurred even after complete excision of the atrial septum at the time of Stage 1 Norwood in both cases. A novel approach to this problem of resecting the roof of the coronary sinus was utilized to enlarge the interatrial communication.