However, it may cause serious complications under certain circumstances. Patent foramen ovale and atrial septal defect closure is a routine procedure to close holes in the upper chambers of the heart.A test called an echocardiogram is used to diagnose a PFO. The test uses sound waves to create pictures of the beating heart. Percutaneous closure of a patent foramen ovale (PFO) reduces the risk of recurrent cryptogenic stroke specifically in younger patients. A PFO closure fills an opening between your heart's two upper chambers. While an Atrial Septal Defect is always considered a structural abnormality in the heart, everyone at birth has a PFO. 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. If a PFO exists, a little blood can flow between the atria.