Left atrial appendage volume is a valuable predictor of atrial fibrillation recurrence after radiofrequency catheter ablation

Abstract

Objective: To investigate the association between the left atrial appendage (LAA) volume and atrial fibrillation (AF) recurrence after radiofrequency catheter ablation. Methods: We prospectively enrolled sixty-two patients with AF (40 cases with paroxysmal AF, 22 cases with persistent AF) who successfully underwent a first AF catheter ablation and had performed contrast-enhanced cardiac computed tomography (CT) prior to the procedure to measure LAA volumes in our hospital from January 2012 to August 2015. Circumferential pulmonary vein isolation was performed under the guidance of three-dimension mapping system (CARTO system). Linear ablation or ablation of complex fractioned atrial electrograms was also undertaken if necessary. All patients were followed up at the 3rd, 6th and 12th months after ablation by 24-hour ambulatory Holter monitoring, and were divided into the non-recurrence group (n=42) and the AF recurrence group (n=20). Univariate and multivariate Cox proportional hazards regression analysis were used to assess the factors related to AF recurrence. The receiver operating characteristic (ROC) curve was calculated to assess the best cut-off value of LAA volume to predict AF recurrence. Kaplan-Meier method was used to evaluate the rate of freedom from AF recurrence. Results: Mean LAA volume in all patients was (9.5±3.6)ml. AF recurrence occurred in 20 patients (32%) during the follow-up period. The LAA volume was significantly larger in the AF recurrence group than in the non-recurrence group ((11.5±3.8)ml vs. (8.3±3.1)ml, P=0.002). In the univariate regression analysis, LAA volume (HR=1.36, 95%CI 1.14-1.82, P<0.001), persistent AF (HR=4.43, 95%CI 1.52-12.06, P<0.001) and hypertension (HR=1.61, 95%CI 1.13-2.04, P=0.041) were risk factors of AF recurrence. However, multivariate regression analysis revealed that LAA volume (HR=1.32, 95%CI 1.12-1.51, P<0.001) and persistent AF (HR=4.22, 95% CI 1.48-11.05, P<0.001) were independent predictors for AF recurrence after ablation. The receiver operating characteristic (ROC) curve analysis revealed that a LAA volume >8.80 ml was associated with AF recurrence after ablation (sensitivity: 94% and specificity: 66%, area under the curve=0.76). Kaplan-Meier analysis showed a lower rate free from AF recurrence in the group with LAA volume >8.80 ml (P<0.001). Conclusion: Larger LAA volume is associated with AF recurrence after catheter ablation in patients with AF. A LAA volume greater than 8.80 ml could be used to predict AF recurrence after ablation.