Intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) facilitates an understanding of the complex cardiac pathology that is not fully delineated in a two-dimensional (2D) echocardiographic evaluation, and it suggests earlier and more precise surgical planning and intraoperative decision making. In the present case, the intraoperative 2D-TEE midesophageal long-axis view indicated a significant narrowing of the left ventricular outflow tract (LVOT) area by a band-like structure that vertically traversed the middle of the LVOT and connected to the anterior mitral leaflet base and the interventricular septum. However, additional 3D-TEE images of the LVOT and their cropped and rendered 2D images showed that web-like tissue, which presumably had grown around the patch closure from a previous atrioventricular septal defect, was obstructing the LVOT partially.