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. Some adults with PFOs also suffer from migraine headaches. Most people don't have symptoms. Dizziness, vertigo, swaying and loss of balance. A test called an echocardiogram is used to diagnose a PFO. The test uses sound waves to create pictures of the beating heart. Most of the time, PFO itself causes no symptoms. Sometimes symptoms do result from the complications of PFO, like stroke.