What is patent ductus arteriosus (PDA)?
Patent ductus arteriosus (PDA) is a congenital heart defect wherein a child's ductus arteriosus fails to close after birth. Symptoms include shortness of breath and cardiac arrhythmia, and may progress to congestive heart failure if left uncorrected.
In the developing fetus, the ductus arteriosus (DA) is a shunt connecting the pulmonary artery to the aortic arch that allows much of the blood from the right ventricle to bypass the fetus' fluid-filled lungs. During fetal development, this shunt protects the lungs from being overworked and allows the right ventricle to strengthen. When the newborn takes its first breath, the lungs open and pulmonary pressure decreases below that of the left heart. At the same time, the lungs release bradykinin to constrict the smooth muscle wall of the DA and reduce bloodflow. Additionally, because of reduced pulmonary resistance, more blood flows from the pulmonary arteries to the lungs and thus the lungs deliver more oxygenated blood to the left heart. This further increases aortic pressure so that blood no longer flows from the pulmonary artery to the aorta via the DA.
In normal newborns, the DA is closed within 15 hours after birth, and is completely sealed after three weeks. A nonfunctional vestige of the DA, called the ligamentum arteriosum, remains in the adult heart.In patent ductus arteriosus, the newborn's ductus arteriosus does not close, but remains patent. Patent DA is common in infants with persistent respiratory problems such as hypoxia, and has a high occurrence in premature children. In hypoxic newborns, too little oxygen reaches the lungs to produce sufficient levels of bradykinin and subsequent closing of the DA. Premature children are more likely to be hypoxic and thus have patent ductus arteriosus because of their underdeveloped heart and lungs.
A patent ductus arteriosus allows oxygenated blood to flow down its pressure gradient from the aorta to the pulmonary arteries. Thus, some of the infant's oxygenated blood does not reach the body, and the infant becomes short of breath and cyanotic. The heart rate hastens, thereby increasing the speed with which blood is oxygenated and delivered to the body. Left untreated, the infant will likely suffer from congestive heart failure, as his heart is unable to meet the metabolic demands of his body.
More information on patent ductus arteriosus
What is patent ductus arteriosus (PDA)? - Patent ductus arteriosus (PDA) is a congenital heart defect wherein a child's ductus arteriosus fails to close after birth.
What causes patent ductus arteriosus? - Some babies are more likely to have PDA, especially premature babies. In premature infants, especially those who have had respiratory distress syndrome, this blood vessel may stay open.
What are the symptoms of patent ductus arteriosus? - Symptoms of patent ductus arteriosus may include fatigue, sweating, rapid breathing, heavy breathing, congested breathing, disinterest in feeding, or tiring while feeding, poor weight gain.
How is patent ductus arteriosus diagnosed? - Your child's physician may have heard a heart murmur during a physical examination, and referred your child to a pediatric cardiologist for a diagnosis.
What're the treatments for patent ductus arteriosus? - Both surgical and non-surgical methods of treatment are available. In premature infants, an intravenous (IV) medication called indomethacin may help close a patent ductus arteriosus.