Anomalous right upper and middle lobe pulmonary venous connections often occur in combination with su- perior sinus venosus defect; TEE is excellent for visualization of this combination but may not vis- ualize other anomalous pulmonary venous con- nections. Cross-sectional imaging with CMR or CCT is ideal for delineating pulmonary venous connections, particularly those that are associated with veins that may be difficult or impossible to image by echocardiography (eg, innominate vein or vertical vein). CMR has the advantages of not involving ionizing radiation and ability to quantify degree of shunting. 3. It is considered standard of care to use echocar- diographic imaging to guide closure of interatrial communications. TEE and intracardiac echocar- diography are the most widely studied and used modalities for guidance of ASD closure. Defect size, defect morphology, atrial rim adequacy, pul- monary venous anomalies, and left atrial append- age thrombus can all be evaluated using TEE. Echocardiography is also used to determine sizing either by balloon diameter producing complete occlusion of the defect ( stop flow diameter) or by direct visualization and measurement using intracardiac echocardiography. Echocardiography can assess for pericardial effusion and for thrombi on wires or devices. TTE has also been studied for guiding percutaneous ASD closure but is not widely used for this purpose. 4. Cardiac catheterization is performed at the time of transcatheter ASD closure. Provided noninvasive imaging is of sufficiently high quality to estimate pulmonary artery pressures and shunt magni- tude, not every patient with an ASD requires a diagnostic catheterization before surgical closure. However, a diagnostic catheterization may be necessary to determine detailed hemodynamics for decision-making or to clarify discrepant or inconclusive noninvasive imaging data. 