Catheter-guided open ligation of a pulmonary artery to left atrium connection.

Congenital malformations causing mild cyanosis can be overlooked. A large intrapulmonary right pulmonary artery to left atrium connection was the unusual etiology of arterial oxygen desaturation and erythrocytosis in an asymptomatic 30-year-old patient. The shunt was not possible to detect at echocardiography. It was closed via a median sternotomy without the aid of cardiopulmonary bypass. A novel technique was to use an angiographic catheter inserted through the wide shunt into the left atrium before the operation to securely identify it at the surgical dissection.