pediatrics
Atrial Septal Defect (ASD)
Introduction
An atrial septal defect (ASD) is an opening in the interatrial septum, causing a left-to-right shunt and volume overload of the right atrium and right ventricle. Children are rarely symptomatic, but long-term complications after 20 years of age include pulmonary hypertension, heart failure, paradoxical emboli, and atrial arrhythmias. Adults and, rarely, adolescents may present with exercise intolerance, dyspnea, fatigue, and atrial arrhythmias. A soft midsystolic murmur at the upper left sternal border with wide and fixed splitting of the 2nd heart sound (S2) is common. Diagnosis is by echocardiography. Treatment is transcatheter device closure or surgical repair. (See also Overview of Congenital Cardiovascular Anomalies .) Atrial septal defects account for about 6 to 10% of cases of congenital heart disease ( General reference ). Most cases are isolated and sporadic, but some are part of a genetic syndrome (eg, mutations of chromosome 5, Holt-Oram syndrome). The combination of an atrial septal defect and 