Types of Atrial Septal Defects

The ostium secundum defect is the most common type of atrial septal defect. It occurs more frequently in females and may occur in a familial pattern over several generations or be part of a genetic syndrome, such as Holt-Oram.


In patients with the Holt-Oram syndrome, the usual cardiac lesion is a secundum atrial septal defect. In this autosomal dominant disorder, the thumb may be hypoplastic and resemble a finger, longer than normal or absent altogether. In this photograph, the thumb is missing, the forearms are shortened and supination of the left hand is limited.