- Etiology: congenital
— Ostium primum (30%) – at level of endocardial cushion, associated with AV canal
— Ostium secundum (60%) – at level of fossa ovale
— Sinus venosus (10%) – at level of superior vena cava, associated with partially anomalous pulmonary venous return, see right atrial enlargement without right ventricle enlargement and collapsed aorta - Complications: Long-term untreated ASD may lead to Eisenmenger physiology seen in 6% of patients with untreated ASD
- Clinical: usually present in adults
Radiology Cases of Atrial Septal Defect
