[Double-chambered Right Ventricle with Difficult Preoperative Diagnosis of Ventricular Septal Defect in Adulthood].

Case 1 is a 65-year-old woman with right ventricular outflow tract stenosis due to dyspnea on exertion. Preoperative echocardiography revealed no shunt between the right and left ventricles. After resecting the right ventricular muscle bundle and weaning from cardiopulmonary bypass, transesophageal echocardiography confirmed a shunt between both ventricles. Right ventriculotomy under second cardiopulmonary bypass revealed a ventricular septal defect (VSD) that was closed with an expanded polytetrafluoroethylene patch. Case 2 is a 58-year-old woman with a double-chambered right ventricle due to dyspnea on exertion. Preoperative echocardiography revealed a perimembranous VSD that coexisted;however, the VSD was completely covered by a membranous septal aneurysm, and no shunt appeared between both ventricles perioperatively. If right ventricular outflow tract stenosis/double-chambered right ventricle has been diagnosed in adulthood, the echocardiographic findings could have differed preoperatively and postoperatively. Combined use with other imaging modalities should improve the diagnostic accuracy of congenital heart disease.