Ventricular septal defect is a very common congenital heart defect. The septum in a normally developing heart is a complete muscular tissue that separates the left ventricle from the right ventricle. If the septum is incomplete due to an abnormality in the development of the embryonic heart, it is called a septal defect and causes blood to flow from the higher-pressure left ventricle to the lower-pressure right ventricle. It can be classified as perimembranous, conical, or myocardial depending on where it occurs, and as large, medium, or small ventricular defect depending on its size and the amount of shunt. The first is the increase of pulmonary blood and the decrease of blood volume in the body circulation due to the left-to-right shunt, which makes the child prone to pulmonary infections in the early stage and pulmonary hypertension in the late stage, while the decrease of blood volume in the body circulation will cause the child to be stunted in growth and development. Second, due to the presence of abnormal blood flow at the ventricular defect and the impact on local tissues, infective endocarditis may occur when germs invade and resistance decreases. Many of you may ask if this disease can be cured without surgery. The answer is yes. Some reports suggest that 20-40% of these patients may heal spontaneously. This spontaneous healing occurs mostly within 5 years of age. The membranous and muscular ventricular defects are the most common, with small to medium-sized ventricular defects having a greater likelihood of healing spontaneously. However, subdry (a type of conus) ventricular septal defects are less likely to heal spontaneously, and since subdry ventricular defects can cause aortic regurgitation, early surgery is recommended for subdry ventricular defects rather than waiting for spontaneous healing. On the other hand, larger ventricular defects will develop pulmonary hypertension earlier. The choice of the timing of treatment lies in the choice of the balance between the self-healing of the ventricular defect and the damage it causes (pulmonary hypertension, aortic regurgitation); if the damage is faster than the self-healing process, then timely intervention is needed, and if the self-healing process is faster than the damage process, then it can wait. In addition, regardless of the size of the ventricular defect, if it has not healed by the age of 5 years, then surgical treatment should be performed to prevent the development of pulmonary hypertension or infective endocarditis. One point to note is that each patient is different and each patient’s condition develops differently. It is important to listen to the specialist’s opinion on the diagnosis and treatment of the disease, rather than taking the initiative to avoid delaying the condition.