Prenatal echocardiographic diagnosis of a right aortic arch and bilateral arterial duct with isolation of the left subclavian artery from the left pulmonary artery

Isolation of the subclavian artery is an uncommon anomaly of the aortic arch system in which one subclavian artery loses its connection with the aorta and arises from the homolateral pulmonary artery by way of a ductus arteriosus. An isolated subclavian artery is always contralateral to the side of the aortic arch. We report the prenatal diagnosis of a right aortic arch and bilateral arterial duct with isolation of the left subclavian artery arising from the left pulmonary artery diagnosed at 25 weeks' gestation by fetal echocardiography.