Ventricular septal defect is the most prevalent intracardiac malformation in congenital heart disease, and the treatment method is mainly direct vision repair under extracorporeal circulation, the heart stops ischemia, so the operation is traumatic, and at the same time, due to the non-normal circulatory perfusion on the lungs, liver, kidneys and nervous system affects more postoperative complications, most patients are not willing to accept. The Department of Cardiac Surgery of Bayi Children’s Hospital continuously explores, studies the clinical, absorbs and learns the new technology of the treatment of precordial disease at home and abroad, and carries out the new technology of treating ventricular septal defect under non-extracorporeal circulation with small incision of transthoracic ultrasound, which is still in the initial stage in China. This technology is still in its infancy in China. The surgeon needs to have surgical technique, interventional blocking technique and cardiac ultrasound imaging technique in the treatment process, which makes this technology of high gold content. There are less than 10 cardiac centers in China that can perform this technique. Our center performs ventricular septal defect blocking treatment through a small incision of 4-5 cm in front of the chest, and the use of this method indicates that our center has taken another important step forward in the treatment of ventricular septal defects without extracorporeal circulation. At present, the smallest child with transthoracic occlusion in our center is 4.9 kg, which is the smallest child in China. This technology not only brings benefits to children of small age and low weight, but also provides a new treatment method for children with severe pneumonia who cannot tolerate extracorporeal circulation. It also provides more options for treatment planning and enriches the treatment options. Traditional medical percutaneous interventional occlusion is highly sought after for its minimal invasiveness, and with the advancement of technology, most atrial septal defects, patent ductus arteriosus, and some appropriate ventricular septal defects can now be treated by this method. However, the indications for percutaneous medical interventional occlusion are still limited, and many patients cannot be treated with this minimally invasive method because of its complexity, prolonged exposure of patients and physicians to x-ray radiation, and difficulties in dealing with unexpected situations. The disadvantages of traditional medical interventional blocking treatment: 1. Large amount of X-ray radiation injury: children undergo an ASD interventional blocking X-ray fluoroscopy time of 15~45 (25±17) min, the larger the dose of X-ray exposure, the greater the injury received. infants and children under 18 months of age receive greater injury. Papadopoulou et al. reported that the risk of fatal cancer or hereditary disease due to X-ray radiation in VSD treated with fluoroscopic interventional occlusion was 4 cases per 1000 cases. 2, arteriovenous puncture on vascular damage: our critical care center, the patient composition is small, and the average age of children operated in our department is 6 months, these children often have imperfect development of femoral arteries and veins, thin vessel walls, small lumen, poor conditions for percutaneous intervention, and a small range of adaptation. 3. For the treatment of ventricular defect, the catheter path is farther after the establishment of the track, which makes it difficult for the operator to operate, and the damage to the vessel wall and myocardium during the operation cannot be avoided, and the accuracy is greatly reduced due to the poor control of the guidewire, which eventually leads to the failure of the treatment. If the intracardiac defect is large, the blocking device cannot be delivered to the defect site through a suitable sheath. It can be seen that percutaneous minimally invasive interventional occlusion therapy is greatly limited in the treatment field of small children. In contrast, ultrasound-guided thoracic small-incision occlusion for ventricular septal defects has become a reality. Transthoracic cardiac ultrasound guidance with a 4~5 cm incision under the sternum into the thoracic cavity avoids long intravascular operations, and the whole process is free of X-ray radiation and does not undergo the extracorporeal circulation process, resulting in a quick recovery with few postoperative complications. This is not only another revolution in cardiac surgery technology, but also a new chapter in the field of minimally invasive treatment in cardiac surgery. Advantages of transthoracic blocking for ventricular septal defect: 1.Less vascular damage: Because the blocking path is the free wall of the right ventricle, vascular damage is avoided to the greatest extent. 2.Less risk of blocker dislodgement: The risk of blocker dislodgement is reduced because the blocking path is shorter. 3.Simple operation: the whole process includes: puncture, fixing the sheath, guiding the blocking device, releasing, evaluating, and finally releasing. 4.Firm and accurate position: the operator can clearly perceive the tension of the blocker on the septal defect, and the effect of pushing and pulling experiment is exact, which is helpful for the operator to accurately judge the blocker position . 5.Reducing the appearance of sternal complications: Because the sternum is not completely split, it protects the integrity of the sternum and avoids the risk of chicken chest and funnel chest in children. 6.Non-extracorporeal circulation process: not experience cardiac arrest, avoid non-physiological perfusion, less organism damage, fast postoperative recovery and less complications. 7.No X-ray radiation damage. 8, intraoperative can directly understand the ventricular defect with or without residual shunt and valve with or without regurgitation. 9.The surgical incision is much smaller than the median open incision. 10.If the blockage fails or serious complications occur, the incision can be directly extended and the repair surgery can be changed to establish extracorporeal circulation to save lives. However, not all ventricular septal defects can be treated with this method. For sub-stem ventricular defects, huge perimembranous ventricular defects, and intra-ridge ventricular defects are absolute contraindications to blocking treatment, and the relative limitation of age makes the treatment of ultrasound-guided transthoracic non-extracorporeal ventricular septal defects can only be used as a complementary solution to conventional surgical treatment, and specific analysis is needed for the child’s disease. However, it is inescapable that transthoracic minimally invasive small incision non-external ventricular septal defect treatment has become a new hot spot because of its many advantages, and from the perspective of disease treatment, it cannot be said that it is a new method with cross-age.