Hoping you can tell me, is minimally invasive treatment for atrial fibrillation available?

Yes: All catheter-based techniques are considered minimally invasive. Conventional techniques are up to 75% effective though multiple procedures are frequently required. There is a mini-thoracotomy procedure they can do with slightly improved efficacy over this but it involves making a lot of scar tissue around the left atrium; we usually reserve that for people needing other procedures in the chest.