The primary objective of this study is to demonstrate the safety and performance of the PFx Closure System when utilized for patients with PFOs suffering from cryptogenic stroke, transient ischemic attack, migraine or decompression illness.

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.

Inclusion Criteria:

• Age between 18 and 65 years old
• Documented PFO
• Subjects with one or more of the following:cryptogenic stroke, transient ischemic attack, embolism, migraine headaches, decompression illness

Exclusion Criteria:

• Inappropriate anatomy (vascular or cardiac) or inappropriate medical condition for PFO closure and study medications.