Left-Sided Patent Ductus Arteriosus

W HEN there is a right-sided aortic arch, persistence of a left-sided ductus arteriosus can readily be demonstrated by angiocardiography. This is important because in some types of eyanotic congenital heart disease, such as in the tetralogy of Fallot, anl artificial aortico-pulmonary (Blalock-Taussig' or Pott S2 shunt) is often created in order to alleviate the distress produced by anoxia. Two patients with congenital eyanotic heart disease herein reported had right-sided aortic arches, atretic inain pulmonary arteries, right-to-left shunts at the venltricular level and left-to-right shunts from a patent (left-sided) ductus arteriosus to the left pulmonary artery (pseudotruncus arteriosus). Another patient with triscuspid and maini pulnionary artery atresia had a hypoplastic right ventricle, a right-to-left shunt at the atrial level, a large left ventricle, a dilated aseending aorta with right-sided aortic arch, and a left-sided ductus arteriosus forming a leftto-right shunt with the left pulmonary artery. Demonstration of the patent ductus arteriosus in these cases precluded surgery.