Fetal and postnatal echocardiographic imaging of transposition of the great arteries with the aortic valve posterior to the pulmonary valve.

Transposition of the great arteries (TGA) with a posterior aorta is an uncommon but historically important variant of TGA. In this arrangement, the aorta is posterior to the pulmonary valve, maintains fibrous continuity with the mitral valve, and arises from the right ventricle. We present a case of fetal echocardiography demonstrating TGA with a posterior aorta. Postnatal transthoracic echocardiography and intra-operative assessment confirm the anatomy. To the best of our knowledge, this is the first published case of this anatomic lesion by fetal echocardiography.