A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. Most people will not have any signs or symptoms directly from PFO at all.Possible PFO symptoms include: Stroke. Infants with a PFO and no other heart defects do not have symptoms. Some adults with PFOs also suffer from migraine headaches. Most of the time, a PFO itself causes no symptoms. Sometimes symptoms do result from the complications of a PFO, such as stroke. Most people don't have symptoms. These include sudden weakness or numbness, confusion, difficulty seeing out of an eye, or loss of coordination. Key points about patent foramen ovale.