Atrial septal defect (ASD)of the secundum type represents 7% of all congenital cardiac anomalies. Its morphology is variable with regard to its location, size, and number. In adults, the diagnostic accuracy of the two dimensional 2-D transthoracic echocardiography(TTE) method with respect to anatomy is not optimal. The aim of this study was to assess dynamic change of septal defect area during the cardiac cycle using transesophageal three-dimensional(3-D) echocardiography.

2-D and 3-D echocardiography were performed using a multiplane transesophageal probe on 21 patients with a secundum ASD(mean age 28±10years, 7 male). In all cases, qualitative(location, shape, and structure) and quantitative (largest and smallest anteroposterior and superoinferior diameters, defect area) parameters were measured.

3-D echocardiography revealed changes in diameter and shape of the secundum ASD during the cardiac cycle. The average largest and smallest anteroposterior diameters measured by 2 dimensional transesophageal echocardiography were 26.2±4.1mm and 18.7±3.2mm respectively. The average largest and smallest diameter measured by 3-D echocardiography and were 31.7±6.6mm and 18.2±4.0mm. The percent change of diameter estimated by 3-D echo was significantly larger than that estimated by 2-D echo(45.3±9.5% and 26.5±5%, p<0.05 respectively). The average largest and smallest defect area measured by 3-D echo were average 275±130mm2 and 125±89mm2 respectively. The percent change of defect area estimated by 3-D echo was significantly larger than that estimated by 2-D echo(67.4±12% and 26.5±5%, p<0.001 respectively).

ASD has complex dynamic nature according to cardiac cycle. 3-D Echo provides better information on its dynamic geometry, location, extension. 3-D Echo might be useful for the selection of optimal cases for device closure & device selection during catheter based closure of ASD.