The operation of atrial septal defect is not particularly big, but there are certain risks involved in this operation. Atrial septal defect surgery can be performed under interventional conditions, and at the present level of medical technology, it is not necessary to perform open-heart surgery, but only interventional surgery can be performed, so the surgery is not particularly large. If the atrial septal defect is large, for example, if the atrial septal defect is larger than 4mm, it is necessary to perform open-heart surgery, which is a major surgery, and there may be a risk of cardiac arrhythmia, even malignant arrhythmia and sudden death during the operation. Therefore, atrial septal defect surgery is not major if it is an interventional surgery, but it is a major surgery if it is an open-heart surgery.