The clinical manifestations of atrial septal defects are divided into three stages: infancy, childhood and adulthood. Most of the atrial septal defects in infancy are asymptomatic, and the disease is detected by the heart murmur detected by routine physical examination; in childhood, the disease can be manifested as fatigue, shortness of breath after activity, and large shunt cases can lead to insufficient blood volume in the circulation, which affects the development of the affected children with small size, emaciation, fatigue, sweating, and shortness of breath after activity, and because of congestion in the pulmonary circulation and susceptible to bronchiolitis or pneumonia, and when crying with pneumonia or heart failure, the right atrial pressure can exceed the left atrium, and there is a temporary right-to-left shunt and cyanosis; in adulthood, the clinical manifestations may be divided into three phases. Right atrial pressure may exceed that of the left atrium, with temporary right-to-left shunting and cyanosis; heart failure and persistent cyanosis may occur in adulthood.