Repetition Training - More Heart Sounds Patent Ductus Arteriosus Lesson Waveform Anatomy play pause Table of Contents 1Patent Ductus Arteriosus 2Mitral Regurgitation and Aortic Regurgitation 3Mitral Stenosis Severe and Regurgitation Mild - Rheumatic Origin 4Aortic Stenosis Moderate and Regurgitation Mild - Rheumatic Origin 5Tetralogy of Fallot 6Mitral Valve Prolapse with Mid Systolic Click - Standing Practice Quiz This video is an animation of Patent Ductus Arteriosus A#403 (lesson# 1) within course number 1. 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.