levo-Transposition of the great arteries (L-Transposition of the great arteries, levo-TGA, or l-TGA), also commonly referred to as congenitally corrected transposition of the great arteries (CC-TGA), is an acyanotic congenital heart defect (CHD) in which the primary arteries (the aorta and the pulmonary artery) are transposed, with the aorta anterior and to the left of the pulmonary artery; the morphological left and right ventricles with their corresponding atrioventricular valves are also transposed.