Abstract
Echocardiography is the imaging modality of choice to diagnose different types of atrial septal defect and to determine which defects are suitable for catheter occlusion. In addition to assessment of defect size and rims, transoesophageal echocardiography may be used to guide the procedure itself including device placement, procedural complications and post-procedural checks. This review covers a practical approach to this subject and is accompanied by online videos illustrating the technique.