Dictionary: Patent Ductus Arteriosus (PDA)
Patent ductus arteriosus (PDA): The ductus arteriosus is a blood vessel in the heart that connects the aorta to the pulmonary artery in an unborn baby. It usually closes soon after birth. If it doesn't close, it's called a patent (open) ductus arteriosus. A PDA can cause too much blood to flow to a baby's lungs.