The Value of Adjunctive Left Atrial Posterior Wall Isolation on Clinical Outcomes in Atrial Fibrillation Patients: A Systematic Review and Meta-Analysis.

Background: Although pulmonary vein isolation (PVI) remains the mainstream way of atrial fibrillation (AF) ablation. The left atrial posterior wall (LAPW) may contributes to the development of AF as an arrhythmogenic substrate. The efficacy of additional left atrial posterior wall isolation (LAPWI) beyond PVI is in AF patients remains undefined. This study explored the influence of posterior wall isolation (PWI) on clinical outcomes in AF patients.

Methods: PubMed, EMBASE, and Cochrane Library databases were searched for studies comparing the outcomes of AF with and without PWI. The efficacy outcomes were recurrence of all atrial arrhythmia (AA), atrial fibrillation (AF), and atrial flutter (AFL)/atrial tachycardia (AT). The safety outcomes were mainly focused on procedural adverse events.

Results: A total of 16 studies (7 randomized controlled trials (RCTs), 3 prospective studies and 6 retrospective analyses) with 3340 AF patients were enrolled (1550 patients in PVI with PWI group and 1790 in PVI alone group). 12 studies included persistent atrial fibrillation patients, 3 studies with paroxysmal AF patients and 1 study with paroxysmal AF and persistent AF concurrently. Mean follow-up period was 16.56 months. In AF patients, adjunctive PWI obviously reduced the recurrence of all atrial arrhythmias (risk ratio (RR) 0.78 [95% CI 0.64-0.95], $I^2$ = 79%, p = 0.01) and the recurrence of AF (RR 0.68 [95% CI 0.53-0.88], $I^2$ = 75%, p = 0.004); Meanwhile, additional PWI left no impact substantially on lower recurrence of AFL/AT (RR 1.23 [95% CI 0.94-1.60], $I^2$ = 49%, p = 0.12). The results seemed to be no significant differences in occurrence rate of procedural complications between the PVI only and PWI+PVI (RR 1.19 [95% CI 0.80-1.79], $I^2$ = 0%, p = 0.39). In subgroup analyses, the benefit of adjunctive PWI compared with PVI only was more distinct in persistent AF group and cryoballoon ablation group. Notably, adjunctive PWI with radiofrequency ablation may induce a slight increase of recurrent AFL/AT compared with PVI only (RR 1.56 [95% CI 1.02-2.39], $I^2$ = 30%, p = 0.04).

Conclusions: Compared with PVI alone, additional PWI to PVI appeared to be associated with decreased recurrence of AF and atrial arrhythmias without an increased occurrence of procedural complications, especially in persistent AF patients. Cryoballoon ablation seemed more suitable for PWI compared with radiofrequency ablation. More RCTs are needed to verify the conclusion.