Congenital heart disease is the most common type of congenital malformation. Hearts with local anatomical abnormalities caused by disorders in the formation of the heart and large blood vessels during human embryonic development (within the first 2-3 months of pregnancy) or failure to close channels that should close automatically after birth (which is normal in the fetus) are called congenital heart disease. Congenital heart disease is divided into three groups mainly based on hemodynamic changes. 1. Right-to-left shunt group (cyanotic type): The malformations included in this group also constitute abnormal traffic within the cardiovascular cavity on the left and right sides. The venous blood in the right cardiovascular cavity is shunted into the left cardiovascular cavity through the abnormal traffic, and a large amount of venous blood is injected into the body circulation, so persistent cyanosis can occur. Such as tetralogy of Fallot, triplet of Fallot, double outlet of right ventricle and complete transposition of the great arteries, permanent arterial trunk, etc. 2. Left-to-right shunt group (latent cyanotic type): This type has abnormal channels between the left and right sides of the heart in the blood circulation pathway. In the early stage, because the pressure of the left side of the body circulation of the heart is greater than the pressure of the right side of the pulmonary circulation, the blood flow normally shunts from the left to the right without bruising. When the pressure in the pulmonary artery or the right ventricle increases and exceeds the pressure in the left side of the heart due to crying, breath-holding or any pathological condition, the blood can be shunted from the right to the left and temporary cyanosis can occur. For example, atrial septal defect, ventricular septal defect, patent ductus arteriosus, main pulmonary artery septal defect, and aortic sinus aneurysm breaking into the right heart or pulmonary artery. 3.No shunt type (no cyanosis): That is, there is no abnormal access and shunt between the left and right sides of the heart or between the arteries and veins, and no cyanosis is produced. It includes aortic constriction, pulmonary valve stenosis, aortic stenosis as well as pulmonary valve stenosis, simple pulmonary artery dilatation, primary pulmonary hypertension, etc.