Patent foramen ovale (PFO) is a hole between your heart's upper chambers. 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. PFO is a common occurrence, affecting one in four people. A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should after birth. A patent foramen ovale (PFO) is a hole in the heart that didn't close the way it should after birth. 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. Planned intracardiac echocardiography). Patent foramen transcatheter repair is a procedure to fix this hole in the heart.