Patent Ductus Arteriosus
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(rollover to compare with closed) What Are Its Effects?

The persistence of the Patent Ductus Arteriosus (PDA) after birth causes difficulties because it allows the mixing of oxygen-poor blood being carried to the lungs by the pulmonary artery with oxygen-rich blood being carried by the aorta to the body. If the ductus arteriosus remains open (patent), heart failure may occur.

In some congenital heart defects (eg. Tricuspid Atresia, Hypoplastic Left Heart), the PDA is actually a benefit as it allows necessary mixing of blood. However, when the PDA closes, as it normally does soon after birth, children with these defects experience problems which require treatment.

The rollover diagram to the left shows the dramatic affect of PDA closure in a heart affected by Tricuspid Atresia. This is represented by the change in color of the blood (the redder, the higher the oxygen concentration).