Glossary of Terms

Patent ductus arteriosus
Patent ductus arteriosus is a remnant of fetal circulation, and is an opening between the aorta and pulmonary artery. Its fetal purpose is to shunt blood away from the nonfunctional (collapsed) lungs. The ductus arteriosus normally closes spontaneously soon after birth, usually within 72 hours but may take as long as 2 weeks. Failure of the patent ductus arteriosus to close occurs most often in premature infants. Such infants may develop congestive heart failure because the left-to-right shunt increases blood flow to the lungs and left atrium.