Eisenmenger's complex is a ventricular septal defect combined with pulmonary high blood pressure, the passage of blood from the right side of the heart to the left (right to left shunt) and an enlarged right ventricle. It may also include a malpositioned aorta that receives blood from both the right and left ventricles (an overriding aorta). Without early surgical correction of the underlying defect, such changes may cause progressive damage small blood vessels in lung tissue (pulmonary vascular disease).