Severe coronary sinus dilatation after a modification of the classic Fontan operation: successful resolution with a revision Fontan operation.

Two patients with functional single ventricle and a left superior vena cava, which drained to the coronary sinus, are presented. Each had undergone a Fontan modification that incorporated the coronary sinus into the Fontan pathway. Each developed severe right atrial and coronary sinus dilatation. Revision of a Fontan with an intraatrial lateral tunnel and an extracardiac conduit resulted in improved functional capacity of the patients.