The Paradigm II Trial: PFX Closure System in Subjects With Cryptogenic Stroke, Transient Ischemic Attack, Migraine or Decompression Illness

Inclusion Criteria: * Subject is between 18 and 65 years old * Documented patent foramen ovale as determined by positive micro bubble study demonstrating right to left shunt and/or anatomic detection and functional assessment by pre-operative transcranial Doppler (TCD) and peri-operative echocardiography or ultrasound. * Subjects with one or more of the following: * history of cryptogenic stroke, transient ischemic attack (TIA) or embolism due to presumed paradoxical embolism through a PFO; or * history of severe migraine headaches, despite attempted treatment with available migraine medications, for whom other specific causes of migraine headache, such as underlying disease or medications, have been ruled out; or * history of severe decompression illness. * Negative pregnancy test in women who are of child-bearing potential * Signed Informed Consent form Additional Inclusion Criteria for Migraine Subjects: * Onset of migraine before age of 50 years * History of migraine \> 1 year * Migraine frequency greater than 1 migraine per month Exclusion Criteria: * Presence of thrombus at the intended site of closure, in left atrial appendage, or documented evidence of venous thrombus in the vessels through which access to the PFO is gained. * Active endocarditis, or other infections producing a bacteremia * Presence of atrial septal defect(s) or fenestrations which allow shunting * Presence of implanted cardiac valves, pacemakers, cardioverters/defibrillators (ICDs) or vena cava filters. * Subjects with coagulation disorders or bleeding disorders including gastric ulcers, who are unable to take antiplatelet or anticoagulant therapy * Subjects with an intra-cardiac mass, tumor, clots or vegetation * Large, redundant atrial septal aneurysm that would prohibit adequate device access to the PFO or closure of the PFO, in the judgment of the investigator. A coexisting redundant atrial septal aneurysm is considered large if it prohibits the ability of the operator to adequately achieve vacuum suction necessary to achieve PFO closure. * Presence of conduction abnormality requiring pharmacologic or electrical therapy intervention or 1st degree block * Current enrollment in any investigational trial(s) using devices implanted in the vascular system or enrolled in any experimental drug study(ies) within three months of study entry * Religious or other beliefs which would prevent subjects from following all physician directed instructions or prevent compliance with protocol required medications and follow-ups. * Hemodynamic instability or shock * History of diabetes requiring treatment with insulin Additional Exclusion Criteria for Cryptogenic Stroke Subjects: * History of stroke or TIA within the past 14 days * Source of stroke other than paradoxical embolization Additional Exclusion Criteria for Migraine Subjects: * Seizure disorder * Other organic central nervous system disease * Headache as a result of traumatic head or neck injury * Evidence of alcohol, drug or substance abuse within the previous year