This is a case–control study of our experience of mid-term follow-up of 40 children who had a transcatheter closure of very large atrial septal defects group (1). All cases had an atrial septal defect device size more than 1.5 times their weight, a ratio considered a contraindication for trans catheter closure (TCC) in some previous reports. The aim of this study is to report the outcomes and mid-term follow-up of transcatheter closure of large atrial septal defects using two-dimensional conventional echocardiography, tissue Doppler imaging, and four-dimensional speckle tracking imaging, and as such to compare results of same echocardiographic examination of age-matched control group of 40 healthy children group (2). Cardiac MRI was performed on cases group (1) only to detect right ventricle and left ventricle volumes and function and early signs of complications. There was no difference between cases and matched healthy controls in terms of the assessment of left ventricle and right ventricle by two-dimensional echocardiography, tissue Doppler imaging, and four-dimensional speckle tracking imaging. Similarly, there was no statistically significant difference between four-dimensional echocardiography and cardiac MRI in their respective assessment of both left ventricle and right ventricle volumes and function. We also detected no complications by echo or by cardiac MRI after a median follow-up period of 2 years and recorded a complete remodelling of right ventricle volumes in all children studied. This points to the safety and efficiency of transcatheter closure of large atrial septal defects in children on mid-term follow-up.