Atrial Septal Defect (ASD)

Michael P. D'Alessandro, M.D.
Peer Review Status: Internally Peer Reviewed

Etiology/Pathophysiology:
There are 3 types:

• Ostium secundum defect (60% ) occurs as 1-4 cm hole in the fossa ovalis. This is the most common type.
• Sinus venosum defect (10% ) is located near the entrance of SVC and is associated with anomalous pulmonary venous drainage from the right upper lobe into the right atrium.
• Ostium primum defect is in the low atrial septum, and occurs as part of the more complex endocardial cushion defect.

The end result is a left to right shunt.

Pathology:
Not applicable

Imaging Findings:
The left to right shunt causes shunt vascularity with right heart dilation, but the left atrium does not enlarge because blood is shunted across it to the right atrium. Heart size and pulmonart vascular prominence depend on the size of shunt.

DDX:

• ASD
• VSD
• PDA
• ECD

References:
See References Chapter.

Section Top | Title Page

See related Provider Topics Congenital Heart Disease, Genetics/Birth Defects or Heart and Circulation.

See related Patient Topics Congenital Heart Disease, Genetics/Birth Defects or Heart and Circulation.

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