NCIt definition : A persistent opening in the atrial septum after birth. While a normal part of fetal
circulation, the foramen ovale should close once the newborn begins breathing and
the pressure in the left atrium exceeds that of the right atrium. While a PFO is generally
asymptomatic, it can lead to the passage of clots from the venous circulation into
the artierial circulation, resulting in paradoxical emboli, and possible strokes.;