A patent foramen ovale (PFO) is a hole in your heart that fails to close naturally after birth. This hole is located in the atrial septum, the wall that separates your heart’s top two chambers, known as the atria. This is a fairly common condition, occurring in about 25% of the general population.
It’s unclear what causes the foramen ovale to remain open in some people, although genetics may play a role. This condition is sometimes found with other conditions, such migraines with auras or strokes. Studies have shown that PFO is associated with an increased risk of stroke, especially among those under age 55. However, most people with this condition never have a stroke.