Left Atrial Diameter as a Risk Factor for Atrial Fibrillation Recurrence after Surgical Ablation: A Systematic Review and Meta-analysis

Background: Surgical ablation (SA) is widely performed to eliminate atrial fibrillation (AF) and maintain atrial contraction. A larger left atrial diameter (LAD) has long been associated with the late recurrence of AF post-ablation. Objectives: We conducted a meta-analysis to assess the relationship between LAD and AF recurrence after SA and investigated the effect of LAD cut-off values on the probability of AF recurrence via subgroup analysis. Methods: The literature search was performed in the MEDLINE and Cochrane Central Register of Controlled Trials databases, from inception to July 2021. A random-effects model was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). From 401 initial articles, 16 studies, comprising a total of 4,291 patients, were included in this review. Results: A meta-analysis of 10 studies (2,599 patients) demonstrated that the predicted probability of AF recurrence was 7% greater with each 1 mm increase in LAD (OR: 1.07; 95% CI: 1.04–1.09; P<0.01). Meanwhile, subgroup analysis revealed that the larger the cut-off value, the higher the risk of AF recurrence. The synthesis effect value (OR: 2.45; 95% CI: 1.77–3.39) was close to the OR when the LAD cut-off value was 55 mm (OR: 2.56; 95% CI: 1.22–5.38). Conclusions: In conclusion, a larger LAD is a significant risk factor for predicting AF recurrence after SA. More rigorously designed studies with larger sample sizes are needed to identify the best cut-off value of LAD when performing SA.