Abstract

1. Abstract

Foramen ovale is a physiological channel during the embryonic period of the atrial septum of the heart, which allows umbilical vein blood to flow from the right atrium into the left atrium to maintain fetal blood circulation. If the foramen ovale is still not closed at the age of more than 3 months, or if there is a shunt at the atrial level, it is called Patent Foramen Ovale (PFO). The unclosed foramen ovale is composed of primary septum and secondary septum, with long primary septum and short secondary septum, forming a piece of valve.