A patent foramen ovale (PFO) is a hole in the wall between the heart's two upper chambers (atria). Before birth all babies have this opening.Most people with a patent foramen ovale don't need treatment. PFO closure typically is a cardiac catheterization procedure. Patent foramen ovale (PFO) is a hole between your heart's upper chambers. A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should after birth. Patent foramen ovale closure is a procedure to close a hole in the heart. We use minimally invasive approaches to treat PFO without open-chest surgery. A patent foramen ovale or PFO is a defect in the wall between the two upper chambers of the heart. Patent foramen ovale in cryptogenic stroke: incidental or pathogenic?