The incidence is about 5-10% of congenital heart disease. The murmur of atrial defect is not easy to be heard, and it is often found only when the school-age children are examined, the electrocardiogram shows right bundle branch conduction block, the cardiac X-ray shows more pulmonary blood, enlarged heart shadow, enlarged right atrium and right ventricle, the echocardiogram can clearly diagnose most atrial defects or can be used with the help of acoustic imaging, esophageal ultrasound. The echocardiogram can diagnose most of the atrial defects or with the help of acoustic imaging or esophageal ultrasound. The atrial defect is located at the site of the foramen ovale, which is the central type or II foramen type; at the lower part connected with the mitral and tricuspid annulus, which is the primary foramen type, or I foramen type; at the location where the superior and inferior vena cava enters the right atrium, which is the vena cava sinus type; and at the coronary venous sinus, which is the coronary sinus type. Unless there is a huge atrial defect, symptoms generally rarely appear in the early stage, and small atrial septal defects can be lifelong without surgery, but some data report recurrent cerebral infarction, which may be related to the atrial septal defect, caused by small emboli in the venous system, entering the left heart through the atrial defect to the arteries of the brain and causing cerebral infarction.