Congenital heart disease, which doctors often refer to as precocious heart disease. Congenital heart disease is not uncommon, with an incidence of about 7 to 8 per 1,000 live births. It is a cardiovascular malformation formed by abnormal development of the heart vessels in the mother during early pregnancy (embryonic stage), and is the most common heart disease in infancy and childhood. Doctors classify congenital heart disease into two major types, non-cyanotic and cyanotic, according to the presence or absence of persistent cyanosis in the child. In a normal heart, there are no abnormal channels between the left and right heart, that is, there is no pathway between the left and right atria, and there is no pathway between the left and right ventricles. When there is an abnormal passage between the left and right heart, the blood will be shunted from the left heart to the right heart and the pulmonary blood flow will increase because the pressure in the left heart is higher than that in the right heart under normal circumstances; however, the child does not appear cyanotic. When the infant cries violently, holds his breath or suffers from heavy pneumonia, the pressure of the right heart exceeds that of the left heart, and the blood shunts from the right heart to the left heart and appears temporarily cyanotic, which is the type of congenital heart disease without cyanosis. The common ones are ventricular septal defect, atrial septal defect and patent ductus arteriosus. The other type of congenital heart disease is cyanosis, in which there is an abnormal channel between the left and right heart, combined with right ventricular outflow tract obstruction (pulmonary stenosis) or very serious pulmonary hypertension, resulting in increased pressure in the right heart and exceeding the left heart, and blood shunts from the right to the left through the abnormal channel between the left and right heart, resulting in persistent cyanosis and reduced pulmonary blood flow. In addition, there may be abnormal origin of large vessels, such as aorta and coronary artery from the right ventricle, and pulmonary artery from the left ventricle, with septal or atrial septal defect, which may result in persistent cyanosis and increased pulmonary blood flow, such as complete transposition of the great arteries. Generally speaking, cyanosis-free type is less severe than cyanotic congenital heart disease and has a single heart malformation, so most children can undergo surgery to cure the malformation; currently, doctors can also perform radical surgery on children with common cyanotic congenital heart disease such as tetralogy of Fallot. Therefore, parents are reminded that when you suspect or know your child has congenital heart disease, the heart must strive for early examination to clarify which type of congenital heart disease belongs to, in order to seize the time for surgery and strive for the best treatment effect.