Patent foramen ovale (PFO) is a hole between your heart's upper chambers. A patent foramen ovale, or PFO, is a special type of hole between the upper chambers of the heart.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. In this procedure, the provider inserts a thin, flexible tube called a catheter into a blood vessel in the groin area. If your health care provider thinks you may have a patent foramen ovale (PFO), imaging tests of the heart may be done. Patent foramen ovale (PFO) is a hole between the left and right atria (upper chambers) of the heart. This hole exists in everyone before birth. Patent foramen transcatheter repair is a procedure to fix this hole in the heart. Normally, the atrial septum separates the right and left atria.