Atrial septal defect (ASD) is one of the more commonly recognized congenital cardiac anomalies presenting in adulthood. ASD is characterized by a defect in the interatrial septum allowing pulmonary venous return from the left atrium to pass directly to the right atrium. Depending on the size of the defect, size of the shunt, and associated anomalies, this can result in a spectrum of disease ranging from no significant cardiac sequelae to right-sided volume overload, pulmonary arterial hypertension, and even atrial arrhythmias.
With the routine use of echocardiography, the detection and, therefore, the incidence of ASD is increased compared to earlier incidence studies using catheterization, surgery, or autopsy for diagnosis.
The subtle physical examination findings and often minimal symptoms during the first 2-3 decades of life contribute to a delay in diagnosis until adulthood, the majority (more than 70%) of which is detected by the fifth decade of life. However, earlier intervention of most types of ASD is recommended.