A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. Most of the time, PFO itself causes no symptoms.Sometimes symptoms do result from the complications of PFO, like stroke. If you have a patent foramen ovale, some bubbles show up on the left side of the heart. Transesophageal echocardiogram. 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. The presence of a PFO is strongly associated with migraine with aura, migraine aura without headache, and chronic migraine. Most people will not have any signs or symptoms directly from PFO at all. Possible PFO symptoms include: Stroke.