With the development of modern medical technology and the popularity of imaging diagnosis and treatment techniques, many children with congenital heart disease are detected by echocardiography in the neonatal period, and atrial septal defect and ventricular septal defect are the most common congenital heart diseases, with an incidence of about 0.1-0.4% in newborns, accounting for 20-30% of all congenital heart diseases. Parents of children with atrial septal defect and ventricular septal defect have varying degrees of questions and confusion about how to determine the severity of their child’s disease, how to choose the appropriate treatment, and what is the best time for surgical treatment. Because the septal defect is located between the left and right atria where the pressure in the heart is low, the fractional flow is much lower than that of the ventricular septal defect, so surgery is generally not needed in infancy and can generally wait until the age of about 1.5 to 2 years before considering surgical treatment. If the ventricular septal defect is small, there is a possibility that part of it may close on its own, especially if it exists in the myocardium, and if it exists under the tricuspid septum, there is a possibility that the fractional flow may be reduced due to adhesions to the surrounding tissue. Even if the defect does not close on its own, it usually does not pose a serious health problem. If the septal defect is large, it can have a serious impact on the child in the first few months of life. After the first 1-2 weeks of life, as the pressure in the right ventricle decreases, blood flow begins to flow from the left ventricle through the septal defect into the right ventricle, where resistance is relatively low, and congestive heart failure gradually develops. Pulmonary artery blood flow then continues to increase, causing the walls of the pulmonary vessels to thicken as a result, producing a severe consequence of increased pulmonary artery pressure, which can develop into cyanosis in later stages. The early increase in pulmonary artery pressure is reversible, but gradually it progresses to irreversible lesions. From a surgical point of view, before the age of half a year, surgery is a high-risk area due to the small weight of the child, the imperfect development of the organs and the fragility of the tissues. When the child weighs 10 kg or more and reaches the age of 1 year or more, the risk of surgery decreases significantly and stabilizes in a lower risk area. We recommend that: 1. When an infant is initially found to have a ventricular septal defect, immediate surgical treatment is usually not recommended, but rather clinical observation or treatment of congestive heart failure with medication to allow the septal defect to close on its own with the continuation of time. 2. When the ventricular septal defect is large, if the child grows well during the first few months, indicating that the size of the ventricular septal defect will not cause congestive heart failure, observation can continue for early surgery after reaching the aforementioned low-risk area. 3. If the child has a large ventricular septal defect with moderate or higher pulmonary hypertension, poor growth in the first few months, combined with congestive heart failure and recurrent respiratory infections, early surgery is often required, even in the high-risk area of surgery, which must be carefully considered by the child’s parents due to the high risk of surgery. It is also important to note that if the size and symptoms of the atrial septal defect and ventricular septal defect do not match, the child should be alerted to the possibility of combining other cardiac malformations and it is recommended to review the echocardiogram or go to a large heart center to confirm the treatment!