Left arm underdevelopment secondary to an isolated left subclavian artery in tetralogy of Fallot.

The anomalous origin of the left subclavian artery is known to be associated with right aortic arch and tetralogy of Fallot. In our case, the left subclavian artery arose from the left pulmonary artery. Therefore, the left arm was perfused by poorly oxygenated blood from pulmonary arteries and some retrograde vertebral artery flow. Thus, the left arm was cyanotic and less developed than the right one. The patient underwent surgical repair with complete correction of tetralogy of Fallot and reimplantation of the left subclavian artery to the left carotid artery.