Coronary Sinus Atrial Septal Defect

Coronary sinus ASD is a rare type of atrial septal defect caused by partial or complete absence of the wall separating the coronary sinus from the left atrium. It accounts for less than 1% of all ASDs and is frequently associated with a persistent left superior vena cava.

The defect creates a left-to-right shunt from the left atrium into the coronary sinus and onward to the right atrium. Right heart volume overload and pulmonary hypertension may develop. The condition is usually diagnosed in childhood but may also be discovered in adulthood.

Diagnosis is made by transesophageal echocardiography, cardiac CT and MRI. Treatment is surgical; depending on defect size and associated anomalies, patch closure or coronary sinus reconstruction is performed.