QUANTITATIVE-ANALYSIS OF THE MORPHOLOGY OF SECUNDUM-TYPE ATRIAL SEPTAL-DEFECTS AND THEIR DYNAMIC CHANGE USING TRANSESOPHAGEAL 3-DIMENSIONALECHOCARDIOGRAPHY

Background A noninvasive method for the determination of size and spat ial relationships of atrial septal defects to adjacent cardiac structu res, which would be advantageous to those contemplating device closure , is described. The aim of the study was to examine the value of trans esophageal three-dimensional echocardiography for this purpose. Method s and Results Three-dimensional reconstruction of transesophageal two- dimensional echocardiography was performed in 17 patients. Left-to-rig ht shunt (by oximetry in 16 of 17 patients) was 2.4 to 16.2 L/min, and the Qp/QS ratio was 1.4 to 4.7. The defect area of the atrial septal defect was measured throughout the whole cardiac cycle each 40 ms from the three-dimensional data set. Results were compared with shunt para meters by oximetry and with intraoperative measurements. Distances bet ween atrial septal defect and mitral and tricuspid annulus and the ori fices of the caval and pulmonary veins were also measured. The atrial septal defect area ranged from 0.2 to 2.4 cm(2) (diastole) to 0.5 to 5 .6 cm(2) (systole). The maximal area at end-systole was 108% of the ar ea at beginning of systole, and the minimal area at end-diastole was 4 3%. The defect area correlated significantly with the Qp/QS ratio (r = .70), and the maximal atrial septal defect diameters as measured by u sing three-dimensional echocardiography correlated well with intraoper ative measurements (r = .87). Distances to mitral and tricuspid annulu s and to the superior caval vein were determined in all patients. Dist ances to orifice of the inferior caval vein were measured in 12 patien ts, and orifices of right pulmonary veins were visible in 5 patients. Conclusions Transesophageal three-dimensional echocardiography of atri al septal defects allows the determination of the instantaneous defect area and its dynamic changes and thus provides valuable information a bout the distances to adjacent cardiac structures. This may have clini cal implications for the selection of patients suitable for interventi onal closure and for the assessment of procedural success.