Aberrant left subclavian artery in tetralogy of Fallot.

The anatomy of the aberrant left subclavian artery in a right-sided aortic arch is different in patients with tetralogy of Fallot than in persons with a normal heart. In all eight patients with tetralogy of Fallot and aberrant left subclavian artery in this series, the left subclavian artery arose directly from the distal aortic arch. In contrast, normal persons with right aortic arch and aberrant left subclavian artery invariably have an aortic diverticulum from which the left subclavian artery and the left ductus arteriosus originate. The possible different embryologic events responsible for these two forms of aberrant left subclavian artery are discussed.