A small hole in the heart is usually referred to as a ventricular septal defect or atrial septal defect, and the severity of the condition is evaluated based on the size and location of the defect. 1. Ventricular septal defect (1) If the ventricular septal defect is larger than 5mm, the blood in the pulmonary circulation flows back to the left atrium, which increases the load on the left heart and gradually enlarges the left heart. The long-term increase in blood flow in the pulmonary circulation can lead to pulmonary hypertension, and the load on the right ventricle also increases, which enlarges the right ventricle and can eventually progress to irreversible heart failure. (2) If the ventricular septal defect is less than 5mm, it may not show symptoms, and may even heal and close by itself before the age of 10. 2. Atrial septal defect (1) Atrial septal defects less than 5mm without obvious symptoms are generally not very serious, such as defects less than 5mm patients, you can choose to observe, regular follow-up. (2) Atrial septal defects greater than 5 mm can cause cyanosis, recurrent respiratory infections, and slower-than-normal development due to lack of oxygen. Some patients may also have serious complications such as heart failure and pulmonary hypertension, which may even jeopardize the child’s life. For patients with ventricular septal defects or atrial septal defects, early detection and treatment are extremely important, and medication, interventional therapy, and surgery can all lead to a better prognosis.