Purpose of the review This study was conducted for diagnosis of secundum ASD in Pediatrics department at Sohag University Hospital to review current different imaging diagnostic modalities for percutaneous device closure of secundum ASD. Index Terms—atrial septal defect, 2DTEE, 3DTEE, ASD IIdevice. Background In children diagnosed with a secundum “atrial septal defect” (ASD II), 3DTEE can reveal anatomic details that improve the efficacy of device closure. Moreover, 3DTEE provides unique en face-view of ASDII. Patients were evaluated also with 2DTEE before and throughout device closure. (7) Conclusion In the vast majority of pediatric patients, transcatheter closure of a secundum atrial septal defect (ASD II) is now preferred to surgical closure. However, multimodality imaging is necessary for accurate patient screening, procedure indication, and the safe and effective delivery of this transcatheter therapeutics. TTE, 2DTEE, and 3DTEE are all options, and there are strong correlation between the maximum diameter of ASD II measured by 3DTEE and those of 2DTEE. ‎