COR LOE Recommendations Diagnostic I B-NR CMR or CTA is recommended for evaluation of partial anomalous pulmonary venous Diagnostic (Continued) IIa B-NR Cardiac catheterization can be useful in adults with partial anomalous pulmonary venous connection to further define Therapeutic I B-NR Surgical repair is recommended for patients with partial anomalous pulmonary venous connection when functional capacity is impaired and RV enlargement is present, there is a net left-to-right shunt sufficiently large to cause physiological sequelae (eg, Qp:Qs 1.5:1), PA systolic pressure is less than 50% systemic pressure, and pulmonary vascular resistance is less than one third of I B-NR Repair of partial anomalous pulmonary venous connection is recommended at the time of closure of a sinus venosus defect or I B-NR Repair of a scimitar vein is recommended in adults when functional capacity is impaired, evidence of RV volume overload is present, there is a net left-to-right shunt sufficiently large to cause physiological sequelae (eg, Qp:Qs 1.5:1), PA systolic pressure is less than 50% systemic pressure and pulmonary vascular resistance is less than one third IIa B-NR Surgery can be useful for right- or left- sided partial anomalous pulmonary venous connection in asymptomatic adults with RV volume overload, net left-to-right shunt sufficiently large to cause physiological sequelae (eg, Qp:Qs 1.5:1), pulmonary pressures less than 50% systemic and pulmonary vascular resistance less than one third systemic.S4.1.2-5 IIa B-NR Surgery can be useful for repair of a scimitar vein in adults with evidence of RV volume overload, with Qp:Qs 1.5:1 or Synopsis Abnormal connection between a pulmonary vein and systemic vein will result in volume overload of the right heart, with a physiological effect similar to that of an ASD. However, in the absence of an associated ASD, a- nomalous pulmonary venous connection differs in that there is no potential for right-to-left shunting, and the magnitude of the left-to-right shunt is not exacerbated by the development of acquired left heart disease. 