The long-term impact of lesion set in the surgical ablation of atrial fibrillation during mitral valve surgery: multi-center propensity-score weighted study.

Objective: This study aimed to assess the effect of the lesion sets for surgical ablation (SA) of atrial fibrillation (AF) on long-term outcomes and identify the optimal lesion set.

Methods: Between 2005 and 2017, 1825 patients underwent SA concomitant to mitral valve (MV) surgery in the participating institutions. Of these, 529 underwent left atrial (LA) ablation, whereas the remainder had biatrial (BA) ablation. The clinical and rhythm outcomes were compared, considering death as a competing event. Inverse probability treatment weighting (IPTW) was used to mitigate the selection bias.

Results: The patients undergoing LA ablation were younger and less frequently had long-standing AF with a shorter duration or required concomitant tricuspid valve surgery. Adjusted analysis showed that LA ablation was associated with a lower risk of early pacemaker implantation (odds ratio, 0.16; 95% confidence interval [CI], 0.07-0.38; p<0.001) than BA ablation. Over a median follow-up of 70.4 months (interquartile 44.1-111.2 months), the LA ablation group presented a higher risk of AF recurrence (subdistribution hazard ratio [SHR]1.26; 95% CI 1.12-1.41; p<0.001), with a 5-year cumulative incidence of 34.2% compared to 28.6% in the BA group. The risk of late mortality (SHR, 1.17; 95% CI, 0.74-1.86; p=0.507) and stroke (SHR, 1.21; 95% CI, 0.82-1.79; p=0.345) did not differ between the groups CONCLUSION: In patients undergoing SA concomitant to MV surgery, both lesion sets provided comparable incidence of mortality and stroke. However, BA ablation was associated with a superior rhythm outcome at the expense of a higher risk of early pacemaker implantation.