Can congenital heart disease (congenital heart disease) heal itself? I believe this is a question that many parents of children with congenital heart disease are eager to know and understand. Before introducing the issue of self-healing, we would like to briefly introduce what is simple and complex congenital heart disease. Precardiac disease is divided into two categories according to its complexity: simple precardiac disease and complex precardiac disease. Simple precardiac disease, in simple terms, is precardiac disease with only one type of abnormality, such as atrial septal defect, ventricular septal defect, patent ductus arteriosus and pulmonary valve stenosis. Complex precardiac disease: two or more malformations are present in combination and they are closely related embryologically, with one of them being the main lesion and the others being concomitant lesions. For example, the most common form of tetralogy of Fallot presents with the coexistence of four malformations, but its embryologic pathogenesis is an abnormality of the conus arteriosus truncus, in which the patient presents with right ventricular outflow tract stenosis as the main lesion and the others as concomitant lesions. In addition, there is the concept of compound malformation, which refers to the combined presence of two or more simple malformations. These compound malformations are embryologically unrelated and are a combination of multiple simple malformations. Current studies have shown that only some of the simple predilections have the possibility of self-healing, whereas no self-healing has been reported for complex predilections, which only get progressively worse with age. The simple precordial diseases with the possibility of self-healing (autoclosure) are as follows: i. Atrial septal defect (atrial defect) Atrial septal defect is one of the most common precordial diseases in infants and children, and because there are no symptoms, many people do not detect it until adulthood, making it the most common adult precordial disease. Usually, there are three types of septal defects: 1) secondary foramen ovale, which is the most common type of defect and refers to what we usually call atrial septal defect; 2) venous sinus septal defect, which is divided into superior and inferior septal type; 3) primary foramen ovale, which is actually a type of atrial septal defect (also called endocardial cushion defect). Among the above septal defects, only small secondary foramen type septal defects have the possibility of automatic closure, while both venous sinus type and primary foramen type septal defects cannot close automatically and must be treated surgically. In infants and children, the self-healing rate of small secondary septal defects (less than 5 mm in diameter) has been reported to be as high as 80%, and most defects of 3 mm or less can close spontaneously, and many septal defects of 3-8 mm can close spontaneously within 3 weeks of age. Therefore, we can wait until the child reaches the age of 3 years before making a decision on the treatment of septal defects of 8 mm or less. Since the early stage of atrial septal defect has less impact on heart and child development, even large atrial septal defects are more appropriate to be treated at the age of 3-6 years unless the child has recurrent pneumonia due to atrial septal defect. Second, ventricular septal defect (abbreviated as ventricular defect) Ventricular septal defect is the most common precordial disease in children, accounting for about 20% of all precordial diseases. It also has the potential to close spontaneously. As with atrial septal defects, the likelihood of spontaneous closure is determined by the location and size of the defect. Overall, about 75% of small ventricular septal defects close spontaneously within 1 or 10 years of birth, but for medium to large septal defects, the rate of spontaneous closure is only 5-10%. If the defect has not closed by 10 weeks of age, it is almost impossible to close. In addition, the rate of closure is also related to the location of the defect. The highest rate of automatic closure is for muscular ventricular septal defects; however, the reported rates vary widely, ranging from 37.9% to 93% for muscular ventricular septal defects within 1 week of age, followed by membrane and perimembranous ventricular septal defects, which also vary widely, ranging from 4.7% to 35% within 1 week of age, and this variation may be related to different populations. The auto-closing rate of other ventricular septal defects is very low, especially the subpulmonary ventricular septal defect, which has a very small chance of self-healing and can damage the nearby valves in the long term, therefore, once these defects are found, they should be treated early, and surgery should be performed at an early date according to the advice of the predilection. Arteriovenous ductus arteriosus is also one of the most common precordial diseases, but its incidence is slightly lower than that of the two aforementioned malformations. The incidence of this disease is related to the geographical location, such as the highland area has a higher incidence. The incidence of ductus arteriosus is significantly higher in preterm than in term newborns, and is higher in low birth weight than in normal weight newborns. It has been reported that the incidence of ductus arteriosus in newborns weighing less than 1.5 kg at birth is more than 30%. Unlike the two aforementioned malformations, the rate of self-healing is not only related to size but also to the birth status of the child, and the time to self-healing is significantly shorter than that of the two aforementioned malformations. In term newborns, under normal circumstances, approximately 50% of the ductus arteriosus closes spontaneously within 24 hours of birth, 90% within 48 hours of birth, and all ductus arteriosus closes within 72 hours. If the ductus arteriosus remains unclosed after 1 week of life, there is no possibility of automatic closure. In preterm infants, the time to autoclosure is significantly longer. Typically, 60% of the ductus arteriosus closes within 3 days of birth and 72%-75% within 3 months of birth. Although it is thought that automatic closure is possible up to 2 years of age, it is generally believed that it is very rare for a ductus arteriosus that remains unclosed after 3 months of life to close spontaneously thereafter. Therefore, if the ductus arteriosus does not close spontaneously after 3 months of life, surgical closure may be considered. Although there is a high rate of spontaneous closure in all three diseases, the possibility of spontaneous closure should be assessed after a thorough evaluation and expert opinion to determine further treatment options, rather than waiting for a miracle to occur, which may delay treatment.