Infants with atrial septal defect of 6 mm may be self-healing, need to follow the doctor’s instructions dynamic follow-up cardiac ultrasound, closely observe the size of the atrial septal defect. Atrial septal defect is a kind of common congenital heart disease in infancy and childhood caused by genetic and environmental factors, which can be manifested by recurrent respiratory infections, feeding difficulties, cyanosis, heart murmur, etc. It is necessary to improve the ultrasound of the heart to clarify the location and size of the defect, and usually with the increase of age, some small atrial septal defects can be healed naturally. If the baby has recurrent infections with age, and the atrial septal defect still exists, the doctor can evaluate the baby and then perform surgery or blocking intervention if necessary.