When is surgery needed on infants with small sinus venosus asd?

Depends: It depends on the size of the hole and the symptoms it creates. Abnormal heart pressures or chamber size, or repeated chest infections are reasons for surgery. Follow up with the cardiologist as they request.

Pulmonary veins: Sinus venosus defects are often associated with abnormal drainage of pulmonary veins. If the right heart is enlarged on echo therapy is indicated.