Why atrial fibrillation recurs in patients who obtained current ablation endpoints with longstanding persistent atrial fibrillation

Purpose: Although several techniques for modification of atrial fibrillation (AF) substrate, such as linear ablation and complex fractionated atrial electrograms (CFAEs) ablation, have been proposed for longstanding persistent AF (LS-AF) and improved the outcome, there was still a certain recurrence rate, even if current ablation endpoints of these techniques were completely achieved. The purpose of this study was to describe the determinants of recurrent AF in patients who obtained current ablation endpoints with LS-AF. Methods and results: In all, 208 consecutive patients who obtained current ablation endpoints with LS-AF were studied. The current ablation endpoints were defined as complete pulmonary vein isolation, bidirectional block of lines, and disappearance of CFAEs. After a follow-up of 19.9 ± 4.1 months, the patients were classified as AF recurrence group and non-AF recurrence group (including patients with sinus rhythm and atrial tachycardia), and 34 (16 %) patients were in the AF recurrence group. The patients in AF recurrence group had higher rates of right atrium (RA) enlargement (67.7 vs. 45.4 %, p = 0.018) and ≥2 procedure times (58.8 vs. 27.0 %, p < 0.001), longer AF duration (82.4 ± 44.8 vs. 50.8 ± 42.8 months, p < 0.001), and larger left atrium (LA) diameter (49.4 ± 6.2 vs. 46.5 ± 5.3 mm, p = 0.007). In the multivariate analysis, RA enlargement, ≥2 procedure times, and AF duration were independent predictors of AF recurrence. Conclusion: RA enlargement, ≥2 procedure times, and AF duration played important roles in AF recurrence in patients who obtained current ablation endpoints. For these patients with AF recurrence who had already underwent ≥2 procedure times, enlarged RA may contribute to other AF foci and/or substrate, and the ablation strategy may be transformed from LA to RA in the next ablation procedures.