Congenital heart disease accounts for about 0.6% to 0.8% of live infants delivered at term, which is a significant number, and based on 30 million births in China each year, there will be about 200,000 new congenital heart disease each year. With the improvement of perinatal care and medical conditions, many children with congenital heart disease can be detected in the neonatal period and the specific type can be confirmed by echocardiography. Among congenital heart diseases, the more common types are atrial septal defects and ventricular septal defects, both of which account for about 20-30% of all congenital heart diseases. The discovery of congenital heart disease in a child certainly brings a lot of worries to the parents and even dilutes the joy of welcoming a new life to a certain extent, after all, the child comes into this world with certain defects. As a cardiac surgeon, I am glad for these parents, because after all, your child is suffering from a relatively simple malformation that can be anatomically corrected through intervention or surgery. The key question is how to determine the severity of the child’s disease, how to choose the right treatment and the best time. From the surgical point of view, before the age of half a year, the child’s weight is small and the organs are not well developed, so the risk of surgery is higher. When the child weighs more than 10kg and reaches the age of 1 year or more, the risk of surgery will be greatly reduced. The normal septum is located between the left and right atria, and the pressure step difference between the left and right atria is relatively small. Even if there is an atrial septal defect, the fractional flow is generally small (unless it is a huge defect or combined with other malformations such as abnormal connection of pulmonary veins), so it is generally not necessary to operate in infancy, and we can usually wait until about 1.5 to 2 years old to consider surgery or interventional treatment. 2. If the ventricular septal defect is small, it may still partially close on its own, especially if it is located in the muscular region, and if it is present under the tricuspid septal valve, it may also reduce the flow due to adhesions with surrounding tissues to form a membranous tumor. Even if the defect does not close on its own, it usually does not pose serious health problems. Such children can be observed clinically, with periodic follow-up echocardiograms to observe changes in the diameter of the defect. 3. If the ventricular septal defect is large, it can have a serious impact on the child in the first few months of life. After birth, as the child’s lungs open and 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 the resistance is relatively low, and congestive heart failure gradually develops. Pulmonary artery blood flow continues to increase, causing the walls of the pulmonary vessels to thicken, resulting in a severe increase in pulmonary artery pressure, which is reversible in the early stages, but gradually progresses to irreversible lesions and develops into cyanosis in the late stages, medically known as Eisenmenger’s syndrome. If the child has a large ventricular septal defect, feeding difficulties, poor development, recurrent pneumonia and heart failure appear very early after birth, early surgery is required. 4. After the child reaches the age of 2 years regardless of the size of the ventricular septal defect, there is a risk of infective endocarditis due to prolonged blood flow impingement and therefore more aggressive use of antimicrobials than in normal children. The chances of self-closing are generally low (except for myocardial defects), and treatment (surgical or interventional) is generally recommended before school age.