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.How is a PFO treated? Treatment is a catheter procedure or surgery to close the opening in the heart. PFO treatment closes the Patent Foramen Ovale (PFO) through blood thinning medicines or a catheter-based procedure to close the hole. However, it may cause serious complications under certain circumstances. In roughly 75 percent of cases, the hole, called a patent foramen ovale (PFO), closes on its own and requires no treatment. 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. This document addresses the transcatheter closure of patent foramen ovale and transcatheter or open left atrial appendage (LAA) closure.