Text Box: ROLE OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN TRANSCATHETER CLOSUR OF ATRIAL SEPTAL DEFECT WITH AMPLATZER OCCLUSION DEVICE Zhang Y-Q, Chen S-B, Sun K, et al Shanghai Children,s Medical Center, Shanghai, China Objective: To evaluate transesophageal echocardiographic guidance for transcatheter closure of atrial septal defect (ASD) with the Amplatzer occlusion device. Methods: Transcatheter closure of ASD was performed using the Amplatzer occlusion device under the guidance of transesophageal echocardiography (TEE) in 53 patients with secundum ASD. Results: 44 of 53 patients had successful implantation of Amplatzer occlusion device. The remaining 9 patients were unsuccessful due to inaccurate measurements of the size, location and morphology of ASD by transthoracic echocardiography. There was significant difference between the size of ASD measured by transthoracic echocardiography and balloon-stretched diamension (P<0.05), although there was a correlation (r=0.87, P<0.01). There was no significant difference between TEE and balloon-stretched diamension (P>0.05), correlation was better than those measured by transthoracic echocardiography (r=0.93, P<0.01). Trivial residual shunt was founded in 6 patients. Conclusions: TEE could clearly demonstrate the location, size and morphology of ASD. It was valuable for patients selection before the procedure, deployment of the Amplatzer occlusion device during procedure and evaluating the therapeutic effects. It was a safe and effective guidance technique. 1852