Patent ductus arteriosus

Patent ductus arteriosus, or PDA, is a simple congenital heart defect that occurs when a connection between the heart’s two major arteries does not close properly after birth. This abnormal connection allows oxygenated blood from the left side of the heart to flow back to the lungs by flowing from the aorta to the pulmonary artery. 
Dr. Robert E. Gross performed the first successful ligation of a patent ductus arteriosus on a seven-year-old girl in Boston in 1938.