Central cyanosis due to prominence of the eustachian and thebesian valves.

A 9-year-old female child with serious central cyanosis was found to have right to left shunt across a large secundum atrial septal defect despite normal right-sided pressures. Preoperative cross-sectional echocardiography suggested the presence of large sinus venosus eustachian and thebesian valves as the mechanism responsible for diversion of the inferior caval and coronary sinus venous return to the left atrium across the interatrial secundum defect. Surgical excision of the unduly prominent sinus venosus valve and patch closure of the atrial septal defect resulted in complete disappearance of the cyanosis and physiological and clinical cure.