Cor triatriatum associated with large atrial septal defect and partial anomalous pulmonary venous return. Case report.

A rare variant of cor triatriatum is presented with a large true atrial septal defect and partial anomalous pulmonary venous return into the right atrium. The correct diagnosis was made at the operation and abnormal left atrial septum was excised completely and a new interatrial septum was created with pericardial patch in such a position that the abnormally drained right upper pulmonary vein was left in the left atrium. It was thought to use the abnormal left atrial septum to close the atrial septal defect by excising only the right lateral border of this abnormal septum and resuturing it to the right atrial wall to close the true atrial septal defect. This thought could not be realized because of the small size of this abnormal septum and large size of the atrial septal defect. This technique can be realized in small or medium sized atrial septal defects associated with cor triatriatum.