The procedure was done under general anesthesia. All the children underwent transesophageal echocardiography (TEE) for reassessment of the defect size and surrounding margins prior to device closure. The ASO was used in all the cases. The device size was selected based on the maximum diameter of the ASD as determined on TEE at 0°, 45°, and 90°. The ASO used was either equal to or about 10% more than the maximum ASD diameter. Balloon sizing was not done in any of the patients. The length of the IAS was measured at 0° and 90° and the longer of the two measurements was used to define the length. Although the IAS length was estimated, it did not determine the maximum size of the device to be used. After obtaining the venous access, heparin was administered in the dose of 100 i.u/kg. Thereafter, 50 i.u./kg of heparin was administered every 30 min if the procedure time extended beyond 60 min. Activated clotting time was not monitored during the procedure. Intravenous (IV) antibiotic was given 1 h before and 8 and 24 h after the procedure. Postprocedure, children were observed for 24 h and were discharged on oral aspirin in the dose of 5 mg/kg/day for 6 months. All of them underwent predischarge ECG and TTE.