Patent ductus arteriosus and its surgical treatment.

The remarkable success that has attended surgical ligation of the patent ductus arteriosus has aroused a new interest in a unique structure and has been the means of revealing striking gaps in our knowledge -of a comparatively common form of congenital heart disease. Unexpectedly, ligation of the infected ductus has shed a new light on the most serious of all forms of heart disease-bacterial endocarditis. Of vital importance in intra-uterine life, during which its purpose is to enable venous blood entering the heart from the superior vena cava to pass directly to the descending aorta and thence to the placenta without traversing the lungs (Barcroft, 1939), the arterial duct persisting after birth forms an arterio-venous fistula. Blood then flows continuously' in large quantities from the aorta to the pulmonary artery. Hence the patent ductus throws an added burden upon the heart and upon the pulmonary and to some extent the peripheral circulations.