BACKGROUND:Occluder closure of atrial septal defect exhibits clear function, safety and efficiency advantages ＜br> OBJECTIVE:Using real-time three-dimensional echocardiography (RT-3DE) technique to evaluate the effect of atrial septal defect occlusion using different occluders on left ventricular structure and motion of the mitral annulus. ＜br> METHODS:Thirty-seven cases diagnosed as atrial septal defect underwent atrial septal defect occlusion, including 20 males and 17 females, aged 20-60 years. The occluder was chosen individual y according to defect size and edge hardness. Conventional and RT-3DE examinations were performed at 1 day prior to occlusion, 1 and 3 months after occlusion. ＜br> RESULTS AND CONCLUSION:Four of 37 patients were withdrawn from the study because of poor RT-3DE results. The other 33 patients harvested good occlusion results. At 1 and 3 months after occlusion, left ventricular end diastolic volume, left ventricular end systolic volume, left atrial end diastolic volume, left atrial end systolic volume were significantly increased (P＜0.05). Moreover, the more increase in these parameters occurred at 3 months after occlusion (P＜0.05). There were no significant changes in left ventricular ejection fraction and mitral annular displacement at three different time points. Left ventricular volume change rate and left atrial volume change rate were positively correlated to the type of occluders, while there was no correlation between endocardial cushion stump and mitral annular displacement. These findings suggest that atrial septal defect occlusion can increase the volume of the left ventricle and left atrium, but exhibit no effect on the motion of the mitral annulus.