Association between left atrial size and atrial fibrillation recurrence after single circumferential pulmonary vein isolation: a systematic review and meta-analysis of observational studies

AIMS: Left atrial (LA) enlargement is associated with atrial fibrillation (AF). However, it is controversial whether dilated atrium can predict post-ablation AF recurrence. We undertook a systematic review and meta-analysis to analyse the association between LA diameter and AF recurrence after single circumferential pulmonary vein isolation (CPVI) and explore the potential mechanism. METHODS AND RESULTS: Electronic databases and bibliographies of retrieved studies were searched. The anteroposterior diameters of LA were available in all included studies, which were measured at end-systole by M-mode transthoracic echocardiography. Subgroup analysis was conducted based on the duration of follow-up. Weighted mean difference (WMD) and 95% confidence interval (CI) were calculated using random-effect or fixed-effect model, depending on statistical heterogeneity. Twenty-two studies with a total of 3750 individuals met the inclusion criteria. The summary WMD of LA diameter between patients with and without recurrence was 1.87 mm (95% CI 1.26-2.48, P< 0.001). Meta-regression analysis of the 22 studies indicated that study design, duration of follow-up, and measurement of asymptomatic recurrences were significant sources of heterogeneity. Sensitivity analysis suggested that the difference in LA diameter between patients with and without recurrences persisted regardless of the duration of follow-up. CONCLUSION: Dilated LA significantly increases the risk of AF recurrence after single CPVI. This is especially applicable to the patients with long-term follow-up.