Transthoracic small-incision atrial septal defect closure Zhu Xianming (Tel 13704719132) Department of Cardiothoracic Surgery, Affiliated Hospital of Inner Mongolia Medical College, Hohhot 010050, Inner Mongolia [Abstract] Objective To investigate the efficacy of transthoracic small-incision atrial septal defect closure in the treatment of atrial septal defect. Methods A 3-cm-long 4th intercostal incision was made on the right side of the sternum, the pericardium was incised and suspended, a double purse string was sewn on the right atrial wall and incised, a delivery catheter (domestic) was inserted into the right atrium and into the left atrium through the septal defect opening, and the septal blocking umbrella was released under ultrasound surveillance via the left chest wall or esophagus, the left and right side umbrella discs were adjusted to clamp the blocking ASD, and repeated pulling tests were done with a safety cord to confirm the appropriate position of the blocking umbrella, Then a mattress suture was made through the right atrial wall and the edge of the umbrella to fix it. The results showed that 39 cases were successfully blocked, and the operation time ranged from 45 to 95 min, with an average of 60 min, and the hospitalization ranged from 3 to 5 d. The blocking umbrella was not displaced and there was no residual shunt in the cardiac ultrasound examination 2 to 24 months after the operation. Conclusion Atrial septal defect sealing under transthoracic ultrasound surveillance is a minimally invasive, safe, and simple treatment method, and this procedure is a new technique worth promoting for surgical + interventional treatment. Keywords: transthoracic small incision; atrial septal defect; occlusion umbrella;