Snapshot A 3-year-old boy presents to his pediatrician’s office for a well-child visit. He recently moved to the United States from Vietnam. He and his parents report no concerns. On physical exam, he is not in acute distress. His cardiac exam reveals a continuous machine-like murmur. There is no cyanosis or respiratory distress. The physician counsels the parents about this murmur and suggests an echocardiogram. Introduction Clinical definition a persistent opening between the aorta and pulmonary artery that fails to close in the immediate postpartum period Epidemiology demographics female > male 2:1 most commonly in premature infants risk factors maternal rubella infection premature infants in utero alcohol exposure Pathogenesis the ductus arteriosus is normal in utero and typically closes hours after birth patency of PDA is maintained by prostaglandin E2 (PGE2) synthesis and low oxygen tension if unfixed, a large PDA can cause left-to-right shunting in the heart, which increases pulmonary blood flow and causes alterations in the pulmonary vasculature shifting of blood from systemic circulation can cause cyanosis over time, with severe defects, this eventually results in pulmonary hypertension and Eisenmenger syndrome Associated conditions fetal alcohol syndrome congenital rubella neonatal respiratory distress syndrome due to persistently low oxygen tension ventricular septal defect Prognosis typically progresses over time Presentation Symptoms symptoms usually occur with larger defects respiratory distress poor feeding poor weight gain easy fatigability Physical exam cardiac auscultation continuous “machine-like" or "to-and-fro” murmur 2nd intercostal space in the left upper sternal border wide pulse pressure bounding arterial pulses cyanosis and clubbing of lower extremities signs of respiratory distress tachypnea grunting nasal flaring retractions during breathing Imaging Radiography indication for all patients views chest findings enlarged pulmonary artery increased pulmonary markings cardiomegaly Echocardiogram indication performed as a diagnostic test most specific test findings ductal flow increased left atrium to aortic root Studies Electrocardiography indications to assess for arrhythmias findings left ventricular hypertrophy can occur over time Making the diagnosis based on clinical presentation and echocardiogram Differential Ventricular septal defect distinguishing factor holosystolic murmur Treatment Management approach many lesions may close spontaneously premature infants often need medical or surgical treatment Medical indomethacin indication first-line therapy for all patients who do not need the PDA premature infants with PDA prostaglandin E indication for patients who require PDA to survive e.g. for patients with transposition of the great vessels Operative surgical closure indication failure of PDA to close after medical therapy term infants with large PDAs Complications Heart failure Eisenmenger syndrome Infective endocarditis