ABSTRACT
The initial assessment of patients for device closure of defects of the interatrial septum usually involves a combination of physical examination and transthoracic echocardiography. Dilation of the right heart is the hallmark of atrial septal defects. Using modern echocardiographic systems with harmonic imaging, skilled operators can almost always determine the nature and size of the defect. Ostium primum and sinus venosus defects are more complex defects not suitable for device closure and these can normally be readily excluded by transthoracic echocardiography. The size and position of secundum defects helps determine the suitability for device closure.
