How serious a condition is a patent foramen ovale?

Not: Most patients with pfo are totally unaware of it's presence.

Mostly benign: This is a small window between the upper heart chambers that is usually blocked off after birth.When baby starts to breathe, the circulation changes, increasing pressure that closes a flap over this window.It can still open if pressures in the upper chambers allow it. Very rarely, a person can pass a clot though that point and trigger a stroke.For most of us, it is of no functional importance.