Abstract: Methods and apparatus for treatment of patent foramen ovale (PFO) provide for applying energy to tissues adjacent the PFO with a catheter device to substantially close the PFO acutely. Apparatus generally includes a catheter device having at least one energy transmission member at or near its distal end configured to apply energy to PFO tissues to acutely, substantially close the PFO. Applied energy may be monoploar or bipolar radiofrequency energy or any other suitable energy, such as laser, microwave, ultrasound, resistive heating or the like. Some embodiments of a catheter device further include one or more tissue apposition members near the distal end for helping bring PFO tissues together, such as a PFO covering member, a vacuum applying member and/or the like. PFO closure via energy-based approaches of the invention may help prevent stroke, treat migraine headache, and possibly treat or prevent other medical conditions.