The apical five-chamber cardiac view can clearly show the size of the ventricular septal defect, the length of the defect stump, and the relationship between the defect and the aortic valve. Most patients can clearly show the location of the ventricular septal defect and the relationship between the defect and the aortic valve in this view. However, in some patients, the location of the ventricular septal defect cannot be shown on this view, and the approximate location of the defect and the size of the defect can be shown with the help of color ultrasound Doppler flow imaging. In some patients, the defect is more than 3mm away from the aortic valve, while the left ventriculography shows that the upper edge of the defect is close to the aortic valve, so it needs to be combined with other parts, especially the long-axis view of the left ventricle for comprehensive analysis. 2. In the short-axis view of the fundus, the size and location of the ventricular septal defect should be observed, and the 9-11 o’clock position on this view is more suitable for blocking treatment. In addition, the distance of the defect from the pulmonary valve should be observed, such as away from the pulmonary valve also helps to judge. 3.Long-axis view of the left ventricle can show the relationship between the upper edge of the ventricular septal defect and the aortic valve, which can help to observe the relationship between the defect and the aortic valve, and whether there is aortic valve prolapse. Whether there is a prolapsed aortic valve blocking the ventricular septal defect. The following are the indications for intervention: 1) myocardial and perimembranous ventricular septal defects; 2) defect diameter of 3-10 mm; 3) the edge of the defect stump is more than 2 mm from the aortic tricuspid valve; 4) left-to-right shunt; 5) no other combined cardiac malformations requiring surgical treatment. Long-axis view of the left ventricle, showing trans-septal flow through the defect and the relationship between the defect and the aortic valve. Transthoracic echocardiographic five-chamber view showing the relationship between the septal defect and the right coronary valve of the aorta, and Doppler shows a left-to-right shunt, with the distance of the defect from the aortic valve greater than 2 mm. The short-axis view of the fundus shows that the defect is located at 11 o’clock, which is a perimembranous ventricular septal defect, and if the defect is more than 2 mm from the aortic valve in combination with the apical or parasternal five-chamber heart view, intervention can be successfully performed. The success rate of intervention for ventricular septal defects meeting the above conditions can reach 99%, especially for small and well-margined ventricular septal defects can be successfully treated. Preoperative ultrasonography can reliably predict success. Unsuccessful interventional treatment of ventricular septal defects is mainly due to proximity to the aortic valve, proximity to the tricuspid valve, and defects that are too large, e.g., greater than 10 mm, except for a very few cases in which blocking treatment is abandoned due to the intraoperative development of an atrioventricular block chamber.