Background—Currently available catheter techniques for closure of a patent foramen ovale (PFO) rely on the placement of an implantable closure device. The objective of the Paradigm I study was to evaluate the safety and feasibility of transcatheter closure of PFO using radiofrequency energy without an implanted device in patients with cryptogenic stroke or transient ischemic attack.

Methods and Results—Thirty patients were enrolled (15 females; mean age 48 years). Mean PFO size was 8.5±2.7 mm. Technical success (ie, successful application of radiofrequency energy) was achieved in 27 patients. The remaining 3 patients received an implantable closure device. All 30 patients were free from serious procedure-related adverse events. No recurrent strokes, deaths, or perforations occurred as a result of the procedure. The mean follow-up was 6 months, and 13 (43%) of the 30 patients experienced PFO closure after the first procedure. Nine of the patients whose PFOs remained patent after the first procedure elected to receive a second procedure using radiofrequency. The PFO was closed for 6 of those patients after the second procedure, which resulted in a secondary closure rate of 63%.

Conclusions—This study demonstrates that transcatheter closure of an intracardiac defect without a permanent implant is technically feasible. Achievement of improved primary closure rates through technique and device modifications will warrant randomized clinical comparison to permanently implanted devices.