Most of the time, a PFO itself causes no symptoms. Sometimes symptoms do result from the complications of a PFO, such as stroke.The foramen ovale is a hole in the wall between the left and right atria of every human fetus. This hole allows blood to bypass the fetal lungs. A patent foramen ovale is a small, flaplike opening in the wall between the upper chambers of the heart. Discusses patent foramen ovale, which is an opening in the septum of the heart between the upper right and left chambers. Covers diagnosis and treatment. Most people will not have any signs or symptoms directly from PFO at all. Possible PFO symptoms include: Stroke. Our expert heart surgeons can close the hole.