A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. Infants with a PFO and no other heart defects do not have symptoms.Some adults with PFOs also suffer from migraine headaches. Most people will not have any signs or symptoms directly from PFO at all. Possible PFO symptoms include: Stroke. If you have a patent foramen ovale, some bubbles show up on the left side of the heart. Transesophageal echocardiogram. Most of the time, PFO itself causes no symptoms. Sometimes symptoms do result from the complications of PFO, like stroke. The larger the hole, the more likely symptoms are.