Poor negative remodeling of left atrium after catheter ablation for nonparoxysmal atrial fibrillation is a risk of very late recurrence

Abstract

Purpose: It has been reported that some patients receiving catheter ablation for atrial fibrillation (AF) suffer from very late recurrence (VLR; initial recurrence >12 months after AF ablation), but its pathophysiology has not been fully elucidated. To evaluate it, we analyzed the left atrial function of nonparoxysmal AF patients who underwent catheter ablation by multi-detector computed tomography (MDCT). Methods: We retrospectively evaluated 56 patients who underwent initial ablation for drug-refractory persistent or longstanding persistent AF in our institute and had no AF recurrence in the initial year after ablation. We followed them for average 1.9±0.8 years and divided them into 2 groups based on the presence or absence of VLR (VLR-group, and NR-group, respectively). All patients were submitted to 128-slice MDCT scan before and 3 months after ablation for electroanatomic mapping integration, pulmonary veins anatomy delineation, and estimated LA volume (LAV) including maximum LAV during cardiac cycle (maxLAV) and LA emptying fraction (LAEF). Then, we compared them between groups. Results: Out of 56 study subjects, 6 patients experienced VLR. There was no significant difference between the groups in the preoperative LAEF (NR-group vs. VLR-group, 20±13% vs. 22±11%, P = 0.74), and preoperative maxLAV (80±28 mL vs. 72±28 mL, P = 0.45). Postoperative maxLAV tended to be larger in VLR patients than in NR patients (60±20 mL vs. 71±30 mL, P = 0.18). The reduction rate of maxLAV was significantly better in NR patients than in VLR patients (-22±19% vs. +2.0±28%, P = 0.002). Higher reduction rate of maxLAV was associated with lower risk of VLR. (Hazard ratio = 0.96, P = 0.04). Conclusions: Poor negative remodeling after ablation to non-paroxysmal AF is a risk factor of VLR. This data indicated that LA negative remodeling by maintaining sinus rhythm acts an important role to maintain sinus rhythm after ablation for nonparoxysmal AF.