Patent Foramen Ovale has been implicated in the etiology of paradoxical embolism, cryptogenic stroke, transient ischemic attack, and right to left gas embolism in severe decompression illness. An association between patent foramen ovale and severe migraine headaches has also been reported. Several implantable devices are being used for percutaneous closure of patent foramen ovale; this study uses a non-implantable system to safely effect closure with the application of radiofrequency energy.