[Incidental diagnosis of an ostium-secundum-type interatrial communication during coronary surgery].

Preoperative assessment of a 73-year-old woman scheduled for coronary revascularization revealed signs of severe disease in three coronary vessels, mild mitral valve insufficiency, moderate tricuspid insufficiency and moderate-to-severe pulmonary hypertension, with preserved left ventricular function. During surgery pulmonary artery catheter measurements confirmed pulmonary hypertension and the presence of very high cardiac output, leading to suspicion of atrial septal defect. Peripheral vein and right atrial blood samples revealed a sudden increase of 23 mm Hg in PO2 and of 22% in oxygen saturation. Finding the opening in the wall of the right atrium gave diagnostic confirmation of an ostium secundum defect 3 cm in diameter. The defect was closed and the coronary vessel bypasses were created. Upon weaning from extracorporeal circulation, the sudden oximetric increase was seen to have disappeared and pulmonary artery pressures had decreased. Postoperative course was satisfactory, with normal sinus rhythms alternating with episodes of atrial fibrillation. We stress the importance of invasive hemodynamic monitoring and transesophageal echography during heart surgery to confirm diagnoses that have not been established during preoperative assessment.