Title: AMPLATZERTM PFO Occluder Post Approval Study. Description: The purpose of this research study is to collect additional information on the safety and effectiveness of the commercially approved AMPLATZERTM PFO Occluder. A maximum of 1214 adults subjects will be enrolled at up to 100 centers in the US and Canada. Subjects will have follow-up at 1 month, 6 months, 12 months, and annually thereafter through 5 years post implant. 4 Key Inclusion/Exclusion Criteria including Age Range If Applicable: Key Inclusion Criteria, 1. Subjects with a PFO who have been determined to have had a cryptogenic stroke (i.e., stroke from an unknown cause) within the last 270 days, Key Exclusion Criteria 2. Age less than 18 years or greater than 60 years at time of consent, 3. Other causes of stroke, 4. Anatomy or vasculature that prevents implantation of the AMPLATZERTM PFO Occluder device.