A normal human heart is divided into four chambers: the left ventricle, right ventricle, left atrium, and right atrium. The circulation in a normal person involves venous blood entering the right atrium, passing through the mitral valve into the right ventricle. The right ventricle then contracts and pumps blood into the lungs. After exchanging gases and becoming oxygenated, the blood turns bright red. It then returns to the left atrium. From the left atrium, blood passes through the mitral valve back into the left ventricle, and then the left ventricle contracts and pumps blood throughout the body. Therefore, there is a thick wall between the normal left and right ventricles, known as the ventricular septum. If due to congenital heart disease or other reasons, a small hole appears in the ventricular septum, it is called a ventricular septal defect. If this defect is large, it necessitates active surgical treatment because if the defect exists, the pressure of the blood flow in the left ventricle is higher, causing a large amount of abnormal blood to enter the right ventricle. This leads to a significant accumulation of blood in the right ventricle, causing the patient to have too much blood in the pulmonary circulation, making the patient prone to recurrent colds and infections. Furthermore, these children may easily develop heart failure and even life-threatening conditions such as infective endocarditis.