InterSEPT: In-Tunnel SeptRx European PFO Trial

Inclusion Criteria: * The patient must be ≥ 18 years of age and ≤ 70 years of age * The patient is willing to comply with specified follow-up evaluations * The patient or legally authorized representative has been informed of the nature of the study, agrees to its provisions and has been provided written Notice of Informed Consent, approved by the appropriate Ethics Committee (EC) * PFO flat width of 4-14mm (approximate PFO balloon diameter of 2.5-9mm) and PFO length of 4-20mm Exclusion Criteria: * Pregnant or nursing subjects and those who plan pregnancy in the period up to 1 year following index procedure * Other medical illness (e.g., cancer, known malignancy, congestive heart failure, organ transplant recipient or candidate) or known history of substance abuse (alcohol, cocaine, heroin etc.) * Known hypersensitivity or contraindication to aspirin, heparin, clopidogrel/ticlopidine, Nitinol, and/or contrast sensitivity that cannot be adequately pre-medicated * Currently participating in another investigational study, or participation in another clinical trial in the previous 3 months * PFO flat width \<4mm or \>14mm to begin the trial. PFO flat width \<4mm or \>19mm when the second size device is ready * PFO length \<4mm or \>20mm * Active endocarditis, active bacterial infection, or other infection producing bacteremia or sepsis * History of chronic or sustained arrhythmia * Congenital or structural heart disease other than PFO * Thrombus at the intended site of implant or documented venous thrombosis in venous access * Severe pulmonary hypertension * Vascular anatomy unable to accommodate the appropriate-sized sheath for device introduction * Acute appendicitis * Confinement to bed (increased risk for clot formation) * Prior cardiac surgery, including implantation of active cardiac devices