Ventricular septal defect is one of the more common cardiac malformations in pediatric congenital heart disease (congenital heart disease), accounting for about 30%-50% of all congenital heart diseases, and is due to impaired development of the ventricular septum during embryonic development of the heart. The defect can exist alone or in conjunction with malformations such as pulmonary stenosis, atrial septal defect, patent ductus arteriosus, and aortic malposition. The disease is slightly more common in boys. What are the details of the clinical diagnosis of ventricular septal defect? Heart murmur is the main sign, electrocardiogram shows left ventricular hypertrophy, heart x-ray shows enlarged heart shadow, enlarged left heart, increased pulmonary blood, echocardiography can be clearly diagnosed. The ventricular defect is divided into perimembranous, double subarterial (substem) and myocardial defects. The double subarterial type cannot close spontaneously, while both myocardial and membranous ventricular defects have the possibility of closing spontaneously. Therefore, if the defect is small, does not affect the child’s development, does not have recurrent pneumonia, heart failure, or severe pulmonary hypertension, it can be reviewed at the age of 2 years under medical follow-up, and approximately 30-40% can heal spontaneously. If they fail to close, then elective surgery can be considered. However, if the pneumonia is recurrent in infancy, if the heart is sad and difficult to control with medication, or if it is accompanied by severe pulmonary hypertension, surgery is required within 1 year of age. In some cases of acute pneumonia with severe heart failure, emergency surgery may also be performed. Surgical results are still satisfactory, and non-surgical catheter interventional closure is still being investigated for myocardial defects. Ventricular septal defects can occur in any part of the ventricular septum, and the size of the defect varies, with a diameter of mostly 0.2-3.0 cm. Ventricular septal defects are generally classified as small, medium, and large defects, with defects less than 0.5 cm being considered small; 0.5-1.0 cm being considered medium; and greater than 1.0 cm being considered large. Ventricular septal defects are mostly single, but several defects can be present at the same time. In children with medium to large septal defects, a large amount of blood flows from the left ventricle to the right ventricle through the defect at the ventricular level (because the systolic pressure of the left ventricle is significantly higher than that of the right ventricle), resulting in a decrease in the blood displacement of the left heart and an increase in the blood volume of the pulmonary circulation and the volume load in the ventricle, which inevitably affects the growth and development of the child and often results in symptoms in infancy and early childhood, such as wasting, weakness, excessive sweating, shortness of breath, and shortness of breath. The child’s feeding is often interrupted by shortness of breath, slow weight gain, and pallor. In addition, children with ventricular septal defect are prone to repeated bronchitis and bronchopneumonia with cough, recurrent upper respiratory tract infections or lung infections. Respiratory tract infections are more frequent in the cold season. If you find paroxysmal dyspnea and irritability in the evening, you should be alert to the possibility of congestive heart failure, and parents must take their children to the hospital for treatment.