New Content Added – Patent ductus arteriosus and other new heart sounds

We are pleased to announce our latest new content for paying subscribers.  We are continuing our brisk release schedule for new heart sounds, and from today can report that paying subscribers have access to videos of:

  • Atrial septal defect
  • Patent ductus arteriosus
  • Ventricular septal defect
  • Constrictive pericarditis

To whet your appetite, read on to learn more about patent ductus arteriosus:


Patent ductus arteriosus (PDA’s) represent up to 10% of the congenital heart defects in children. The male to female ratio differs in the literature with a male predominance (1:3) to female predominance (1:2). If left untreated, it has an estimated mortality of 1.8% per year in adulthood.

In adults, it tends to be an accidental finding. However, even in small PDAs which are asymptomatic there is an increased risk of endocarditis, if left untreated.

PDA is primarily confirmed with echocardiogram or cardiac MRI.  It is caused by a non-regressed communication between the pulmonary artery and the descending thoracic aorta when the normal physiological closure of the fetal ductus fails to occur.  It is one of the more common congenital cardiac defects.

This persistent vessel causes left-to-right shunting to an extent determined by both the calibre of the PDA and also the pulmonary vascular resistance.  In some patients this leads to potentially large flows between the systemic and pulmonary circulations.  As a consequence blood flow through the lungs may become excessive and lead to pulmonary engorgement.  PDA’s can also lead to Eisenmenger’s syndrome.

Clinical features:

  • Collapsing pulse (in large defects)
  • Thrusting apex beat due to volume overload
  • Left parasternal heave (if pulmonary hypertension is present)
  • Can also have an associated thrill
  • “Machinery” murmur that is continuous, which heard loudest beneath the clavicle, and may also be heard posteriorly
  • May also have a mid-diastolic tricuspid murmur in right sided volume overload
  • In some patients, evidence of heart failure

ECG changes

  • Left atrial dilatation (large PDA)
  • Left ventricular strain (large PDA)
  • Normal in small PDA


In infants, treatment is with intravenous indomethacin – however, this is never used in adults.  The mainstay of treatment of a PDA is either catheter closure or surgical ligation, which entails a thoracotomy.