Cor triatriatum with connection of the accessory atrial chamber to the coronary sinus

A case is reported of cor triatriatum associated with partial anomalous pulmonary venous connection. The communication of the common pulmonary vein (accessory atrial chamber) with the coronary sinus has not been previously reported. This anomaly resulted in a normal pulmonary capillary wedge pressure. Under such circumstances the presence of a third atrial chamber can be detected only by angiographic study.