En-face view of a large atrial septal defect from the right atrial perspective obtained by cropping the free wall of the right atrium from a full-volume three-dimensional data-set encompassing the base of the heart. The morphology and size of the defect can be appreciated and quantitated, as well as the extent of peripheral rims and relationships with surrounding cardiac structures. ASD: atrial septal defect, CS: coronary sinus, RA: right atrium, RV: right ventricle.