Left Mitral Isthmus Ablation Associated with PV Isolation: Long-Term Results of a Prospective Randomized Study

Background: The deployment of an ablation line connecting the left inferior PV to the mitral annulus (mitral isthmus line [MIL]) enhances the efficacy of pulmonary vein disconnection (PVD) in preventing atrial fibrillation (AF) recurrences. Objectives: To investigate the long-term effect of the additional linear lesion in a prospective randomized study. Methods: One hundred and eighty-seven patients (37 females, mean age: 55 ± 11 years) with paroxysmal (126) or persistent (61 patients) AF, were prospectively randomized into two groups: PVD (group A, 92 patients) or PVD combined with MIL (group B, 95 patients), performed by means of an irrigated-tip ablation catheter. Results: Successful disconnection of all PVs was achieved in all patients. A bidirectional block (BB) along the left atrial isthmus was obtained in 72 of 95 (76%) patients in group B, most of whom required additional RF pulses from within the distal CS. A transient ischemic attack occurred in 1 patient of group A, and a cardiac tamponade occurred in 1 patient of group B. At 1 year, 53 ± 5% (group A) and 71 ± 5% (group B) remained arrhythmia free (P = 0.01); subgroup analysis highlights a higher improvement among patients with persistent AF (74 ± 9% vs 36 ± 9%; P < 0.01) than what was observed in paroxysmal AF (76 ± 6% vs 62 ± 6%; P < 0.05); antiarrhythmic drugs were continued in 56% and 50%, respectively, in groups A and B (P = ns). Conclusions: The addition of mitral isthmus line to the PV disconnection allows a significant improvement of sinus rhythm maintenance rate, particularly in patients with persistent AF, without the risk for major complications.