Blomström-Lundqvist C et al. (2007) A randomized double-blind study of epicardial left atrial cryoablation for permanent atrial fibrillation in patients undergoing mitral valve surgery: the SWEDish Multicentre Atrial Fibrillation study (SWEDMAF). Eur Heart J 28: 2902–2908

Atrial fibrillation (AF) often persists after mitral valve surgery (MVS); surgeons are trying to improve success rates by modifying the surgical procedure. Cox–Maze III surgery performed at the same time as MVS might be more effective than MVS alone but involves complex incisions. Although epicardial cryoablative surgery seems promising, no randomized trials have yet compared MVS with MVS plus cryoablation.

Blomström-Lundqvist et al. report a trial involving 69 patients with permanent AF, 35 of whom were randomly assigned to receive MVS alone, and 34 of whom underwent MVS with epicardial left atrial cryoablation. After 6 months, 22 (73.3%) patients in the MVS–cryoablation group had regained sinus rhythm compared with 16 (45.7%) patients in the MVS-only group. At 12 months' follow-up, all of the 22 patients in the MVS–cryoablation group had maintained sinus rhythm compared with 15 in the MVS-only group. Coronary artery disease was identified as a risk factor for failure of cryoablation to prevent AF after MVS.

This prospective, randomized, multicenter, controlled trial—the first of its kind in patients with AF—shows that MVS performed concomitantly with epicardial left atrial cryoablation is more effective than MVS alone. This modified technique restores and maintains sinus rhythm in patients with permanent AF, but the authors stress that larger studies are now needed to confirm the method's long-term efficacy and safety.