Visualization of secundum atrial septal defect using transthoracic three-dimensional echocardiography in children: Implications for transcatheter closure

Background: The objective of this study was to evaluate the efficacy of quantitative measurements of secundum atrial septal defect (ASD) with dynamic transthoracic three-dimensional (3-D) echocardiography. Methods: Twenty-six patients (age, 13 months to 14 years; mean age, 37 months) with secundum ASDs underwent 3-D echocardiographic imaging generated from transthoracic echocardiographic interrogation before surgery. Four specific cut planes were defined: four-chamber view, transverse view, en face view from right and left atrial side. The images obtained from 16 patients clearly demonstrated all four defined cut planes for the quantitative measurement. Results: The defect sizing determined by the 3-D images correlated well with surgical findings. These images may be interactively manipulated to optimize visualization of the defect to allow the cardiologist to perform transcatheter occlusion. A significant correlation was demonstrated to the limbic band tissue assessment by four-chamber and transverse views. Unusual atrial structures such as muscle bands and the foreshortening of the en face view might induce biased measurements. Conclusions: The transthoracic approach was successful in capturing sufficient data to create 3-D images, which can provide an accurate assessment of secundum ASD. The possibility of underestimation should always be taken into account with the en face view. Multiple cut planes were essential to ensure correct sizing for adequate selection of the occluder.