Congenital Abnormalities Patent Ductus Arteriosus Lesson Waveform Anatomy play pause Table of Contents 1Coarctation of the Aorta 2Patent Ductus Arteriosus 3Atrial Septal Defect 4Ventricular Septal Defect 5Tetralogy of Fallot 6Ebstein's Anomaly Practice Quiz This video is an animation of Patent Ductus Arteriosus A#29 (lesson# 2) within course number 2. This is an example of patent ductus arteriosus heard at the pulmonic position.Before birth, the two major arteries—the aorta and the pulmonary artery—are connected by a blood vessel called the ductus arteriosus. Shortly after birth the patent ductus closes and turns into a ligament. However, in certain abnormal circumstances the patent ductus remains open allowing blood to flow from the aorta into the pulmonary artery causing a strain on the right ventricle.The first heart sound is normal. The second heart sound is obscured by a continuous crescendo-decrescendo murmur which runs from the beginning of systole to the end of diastole peaking at the second heart sound.In the anatomy tab you can see an enlarged left atrium and left ventricle and turbulent blood flow from the aorta to the pulmonary artery through the patent ductus.