Mechanisms of Long-Term Recurrence 3 Years After Catheter Ablation of Atrial Fibrillation

Objectives: This study explored the potential mechanisms of long-term recurrence (LTR) of atrial fibrillation (AF) 3 years after AF catheter ablation (AFCA). Background: AF is a progressive disease, and the mechanism underlying long-term recurrence after AFCA is unclear. Methods: Among 2,209 consecutive patients who underwent AFCA, 1,325 (age 59 ± 11 years, 72.5% male) who underwent regular rhythm follow-ups for >3 years were enrolled. Among them, 659 patients remained in sinus rhythm (SR), 327 recurred after 3 to 12 months (short-term recurrence [STR]), 235 after 1 to 3 years (mid-term recurrence [MTR]), and 104 after 3 years (long-term recurrence [LTR]). Two hundred-eighteen recurrent patients underwent repeat procedures: 112, 80, and 26 in the STR, MTR, and LTR groups, respectively. Results: The pre-ablation left-atrial (LA) dimensions were larger in the STR (p < 0.001) and MTR groups (p < 0.001) but not in the LTR group compared with the SR group. Low LA voltages were independently associated with an LTR (adjusted hazard ratio [HR]: 0.57 [0.36 to 0.92]; p = 0.022). Upon the redo mapping, the number of reconnected pulmonary veins (PVs) was 2.0 (interquartile range [IQR]: 0 to 3), 1.5 (IQR: 0 to 3), and 1.0 (IQR: 0 to 2) in the STR, MTR, and LTR groups, respectively (p = 0.030). Post-ablation extra PV triggers were more commonly found in the LTR than STR or MTR groups (LTR 40.9% to STR 19.2%; p = 0.014) during the second procedure. Conclusions: The LTR group had a similar baseline LA size and significantly lower LA voltage than the SR group. In the repeat procedures, the LTR group had fewer reconnected PVs, but extra PV triggers were more common than in the STR and MTR groups.