Eighty-eight patients referred for transcatheter closure of atrial septal or patent foramen ovale defects underwent 3-dimensional transesophageal echocardiography to correlate preclosure anatomy with the morphology and positioning of the atrial septal occluder. Despite the effectiveness of the trancatheter closure and absence of complications, 2 linear indentations of the aortic root by the 2 discs of the device were clearly demonstrated in 16 cases, suggesting caution in the choice of very large occluders.