Congenital communication of a retroaortic innominate vein with both the left and right atria in the presence of a normal coronary sinus.

We report the first known case of a retro-aortic innominate vein providing continuity between both the left and right atria in the presence of a left superior vena cava and a normal coronary sinus. This unusual structure created a bidirectional shunt with clinical desaturation at baseline and it complicated the management of a 9-year-old patient while undergoing mechanical ventilation. An embryologic mechanism that explains the development of this complex remains elusive.