As the name implies, VSD is the traffic present between the right and left ventricles and is formed when there is a pause in the development of the ventricular septum during embryonic development of the heart. The effect of VSD on the organism is mainly determined by its size, the so-called large VSD, i.e., its diameter is comparable to the aortic valve caliber (more than 2/3), and the fractional flow can reach 5-7 times of the pulmonary circulation blood volume, or even more; therefore, in neonates and small infants, if the pulmonary resistance decreases, cardiac function can occur Therefore, cardiac insufficiency, pulmonary congestion and reduced pulmonary compliance can occur in newborns and small infants if the pulmonary resistance decreases, with symptoms such as shortness of breath, pulmonary rales, mild cyanosis of the lips and mouth, refusal to eat, night sweats, and terminal wet chills. Small VSD, i.e., its diameter is less than 1/3 of the aortic valve caliber, the size of the chambers of the heart is normal, its fractional flow only accounts for less than 30% of the pulmonary circulation blood volume, clinically asymptomatic, its activity endurance is no different from that of normal people; such as membrane VSD, myocardial VSD may close naturally, clinical follow-up can be observed, but there are reports that the incidence of infectious endocarditis is significantly higher than that of normal people; subarterial stem VSD, because it can lead to Subarterial VSD should be treated surgically because it can lead to aortic valve prolapse and incomplete closure. The rest are medium-sized VSDs, with symptoms appearing later than in large VSDs depending on their size. It is important to note that the size of VSD cannot be determined by cardiac ultrasound alone, as we know that VSD is not orthogonal and is obscured and disturbed by the heart valves; it should be determined by a comprehensive analysis of the child’s symptoms, signs, ECG, chest radiograph and ultrasound. The size of fetal VSD can change with the further development of the heart and should be examined promptly after birth. Health care measures: 1. No special therapeutic care is needed during the fetal period; 2. Normal delivery can be awaited without special delivery measures; 3. Cardiac ultrasound, chest X-ray (orthopantomogram) and electrocardiogram should be performed promptly after birth; 4. Close observation of the child for symptoms such as shortness of breath, choking, refusal of food, hoarseness, night sweats, pulmonary rales, mild cyanosis of the lips and terminal wet chills; 5. If the above symptoms occur in moderate or above VSD oxygenation may aggravate the condition or even acute left heart failure, dobutamine, digoxin and diuretics may be given; 6. Elective surgery or emergency surgical treatment. Timing of treatment: Depending on the size of VSD, large VSD should be treated surgically within two to three months; medium-sized VSD should also be treated surgically within 12 months. Success rate: The success rate of elective surgery is close to 100%, except for emergency surgery for combined heart failure and pneumonia, according to domestic and international reports. Long-term prognosis: Normal life, study and work can be resumed after treatment.