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Background and Aim: Left atrial (LA) enlargement is associated with paroxysmal atrial fibrillation (PAF) incidence and outcome. The predictive role of the LA size in AF treatment with catheter ablation is still controversial. The aim of this meta-analysis was to analyze the potential association between LA diameter in patients with PAF undergoing ablation and AF recurrence after ablation.

Methods: We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to December 2016 in order to select clinical trial and observational studies, which assessed the predictive role of LA diameter in AF recurrence after catheter-ablation. 2962 patients from 16 studies with paroxysmal AF (PAF) were included.

Results: The pooled analysis showed that after a follow-up period of 19. 66± 8.31 months, patients with AF recurrence had larger LA size compared with those without AF recurrence, with a weighted mean difference (WMD) 2.31 ([95% CI 1.27 to 3.34], P < 0.0001). LA diameter ≥40 mm predicted AF recurrence HR:1.04 [95% CI 1.00 to 1.08], P=0.04), but the best cut-off value, in all included patients, was ≥50mm HR:3.08 [95% CI 1.47 to 6.49], P=0.003).

Conclusions: Enlarged left atrium in patients with PAF undergoing catheter ablation predicts recurrences. The diameter more than 50 mm is the best cut-off of the recurrences of AF, but diameter of 40 mm also can predict recurrences in these patients.