Dyspnea after pneumonectomy: the result of an atrial septal defect.

We report the case of severe hypoxemia attributable to right-to-left shunting through an atrial septal defect after right-sided pneumonectomy that developed in a 70-year-old man. Normal right atrial and pulmonary artery pressures were measured. Right-to-left shunting through a patent foramen ovale is known as a rare complication after pneumonectomy. Our patient, however, demonstrated a true atrial septal defect (septum secundum defect) upon open operative repair of the interatrial connection.