Atrial septal defect (ASD) refers to a defect in any part of the atrial septum that causes communication at the level of the atria. It refers to a hole in the atrial septum, except for the patent foramen ovale. Simple atrial septal defect is one of the most common congenital heart diseases, with an incidence of about 0.6‰ of live births. Most are sporadic, but there is also a familial tendency. Holt-Oram syndrome is ASD combined with upper limb (radius) deformity. Atrial septal defects caused by developmental disorders of the endocardial cushions are located in the lower part of the atrial septum, and the ostium primordium atrial septal defect (ostium primordium ASD) above the atrioventricular valve is not included in the description of this disease.