Atrial arrhythmia recurrence after the Maze procedure: Insights from catheter-based mapping

BACKGROUND The Cox-Maze procedure treats atrial fibrillation (AF) through surgical lesion sets designed to isolate pulmonary veins (PVs) and interrupt atrial reentrant circuits. OBJECTIVE To characterize mechanisms of recurrent atrial arrhythmias after Maze procedures using electroanatomic mapping. METHODS We retrospectively analyzed 86 patients who underwent Maze procedures from 2008 to 2023 and later required endocardial catheter ablation for recurrent AF or atrial flutter (AFl). Electroanatomic mapping assessed lesion integrity, arrhythmia patterns, and ablation outcomes. RESULTS After the 3-month postoperative blanking period, 31.8% of patients had both AF and AFl recurrence, 33.7% had AF only, and 33.7% had AFl only. Pulmonary vein reconnection occurred in 78.3% of patients who initially underwent PV isolation (PVI). Reconnection rates were significantly lower with cut-and-sew Maze III (5%) compared to cryothermal (67%, OR 0.07, p<0.0001) and radiofrequency (RF) ablations (56%, OR 0.11, p<0.0001). Macro-reentrant flutter was inducible in 77.9% of patients during catheter mapping, frequently associated with incomplete linear lesions. Surgical left atrial appendage (LAA)-to-mitral annulus lesions were associated with significantly higher overall flutter (100% vs. 71.2%, p=0.005), left atrial flutter (80% vs. 36.4%, p=0.001), and atypical flutter (90% vs. 50%, p=0.002). Mitral valve repair correlated with increased overall flutter (92.6% vs. 71.2%, p=0.028), cavotricuspid isthmus flutter (55.6% vs. 30.5%, p=0.033), and atypical flutter (81.5% vs. 49.2%, p=0.005). CONCLUSIONS Recurrent arrhythmias post-Maze primarily result from pulmonary vein reconnection and incomplete linear lesions. Cut-and-sew lesions demonstrate greater durability than thermal ablation. Meticulous lesion formation and intraoperative verification may reduce recurrence and improve outcomes.