[Atrial septal defect].

Atrial septal defects (ASDs) represent defects in the interatrial septum that allow left to right shunting. ASD is common, accounting for about 10–15% of congenital heart disease. The clinical consequences of an ASD are associated to the anatomic location of the defect, its size, and the presence or absence of other cardiac anomalies. ASDs are classified based on their anatomic location: primum ASD; secundum ASD; sinus venosus defect, in the wall between the left atrium and the superior vena cava or inferior vena cava; coronary sinus defect (unroofed coronary sinus defect) in the wall separating the coronary sinus from left atrium. Echocardiography is the first choice for the diagnosis of ASD. Magnetic resonance imaging can help to select cases with suspected associated defects such as partial anomalous pulmonary venous connection or patients in whom there are inconclusive echocardiographic findings. CT is one of the best methods for special types of ASD, such as coronary sinus defects or combined with ectopic pulmonary venous drainage. Surgical and transcatheter closure are the treatments for patients with indications.