Preferential shunting of venous return from normally connected left pulmonary veins in secundum atrial septal defect

Abstract Preferential shunting of left pulmonary venous blood across a secundum atrial septal defect, a paradoxical hemodynamic finding, was documented in six patients by indicator-dilution techniques. Subsequent surgical findings excluded anomalous connection of the left pulmonary veins, which can result in similar or identical dye curve patterns. An adequate anatomic explanation for this physiologic paradox was apparent In only one patient.