Effect of Mitral Isthmus Ablation on Recurrence Rates in High-Burden Paroxysmal Atrial Fibrillation.

BACKGROUND Patients with high-burden paroxysmal atrial fibrillation (AF) have a higher rate of AF recurrence after catheter ablation than do those with a lower AF burden. The blockade rate of mitral isthmus (MI) ablation can contribute to the maintenance of sinus rhythm and be high based on the ethanol infusion of the vein of Marshall. MATERIAL AND METHODS Patients with high-burden paroxysmal AF who underwent PVI alone or PVI with additional MI ablation were assigned to the "2C" and "2C1L" groups, respectively, based on 2: 1 propensity score matching. The 12-month freedom from AF or atrial tachycardia was compared between the 2 groups. RESULTS The MI blockade rate was 98.0% in the 2C1L group. There was a higher incidence of first-pass isolation (94.1% vs 79.5%, P=0.034), with a comparable incidence of acute pulmonary vein reconnection (3.9% vs 4.9%, P=1.000) of left PVI circles in the 2C1L group, compared with in the 2C group. Both groups exhibited a minimal incidence of complications, with no statistically significant differences observed between them (3.9% vs 4.9%, P=1.000). During the 12-month follow-up, the 2C1L group demonstrated a lower incidence of recurrent AF, atrial flutter, and atrial tachycardia following the initial ablation procedure than did the 2C group (P=0.045). CONCLUSIONS Among patients with high-burden paroxysmal AF, the combination of PVI and MI ablation decreased the likelihood of AF recurrence, when compared with PVI alone, at 12 months after the procedure.