Abstract
A patent foramen ovale is one of the predisposing factors of neurotic decompression sickness. Transcatheter closure of a patent foramen ovale is effective in the secondary prevention of decompression sickness associated with intracardiac shunt. The size of the umbrella should not be limited to the diagnosis of a patent foramen ovale or an atrial septal defect but should be determined by the supporting force of the soft margin of the atrial septum. The surgical method of patent foramen ovale closure is the same as that of the closure of an atrial septal defect, but the closure umbrella of a patent foramen ovale is different from that of the closure umbrella of an atrial septal defect. The size of the umbrella of the right atrium is larger than that of the left atrium, and it is better to close the atrial septum.