A 25-yr-old female who had undergone surgery for common atrium and atrioventricular septal defect at the age of 9, was found to have residual shunting at the level of the atrioventricular junction. Precordial echocardiography failed to assess the direction of the shunt. Transesophageal echocardiography showed dehiscence of the atrial patch at the level of the atrioventricular junction. Through this defect left-atrium-to right ventricle shunting occurred in diastole, whereas in systole the defect was closed by the juxtaposition of the anterior tricuspid valve leaflet.