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 people don't have symptoms. The larger the hole, the more likely symptoms are. PFOs, on the other hand, are normal before birth but may fail to close after birth. Most children have no symptoms from a PFO unless they also have other heart defects. Learn more about the causes and complications of this condition in which a hole in the heart doesn't close the way it should after birth.