Introduction
Catheter ablation has now been recommended as the first-line therapy for drug-refractory symptomatic atrial fibrillation (AF), even in persistent AF with major risk factors for recurrence[1]. The current cornerstone of the procedure is to completely isolate pulmonary veins. However, pulmonary vein antrum isolation (PVAI) alone is far from enough to maintain sinus rhythm in patients with persistent AF, advocating the application of atrial substrate modification.
Left atrial (LA) linear ablation is one of the most common procedures used in addition to PVAI. In our previous study, compartmentalizing the atria with the fixed ‘2C3L’ approach including bilateral PVAI and three linear ablation lesion sets across the mitral isthmus (MI), left atrial roof, and cavotricuspid isthmus (CTI) is comparable to stepwise ablation[2]. However, failure in MI block and high MI conduction recovery rate are the most important limitations of this approach that attribute to the recurrence of atrial tachycardias(AT). For the similar reason, the STAR AF II trial failed to prove the added value of linear ablation[3].
Ethanol infusion into the vein of Marshall (EI-VOM) has been found effective to achieve MI bidirectional block and facilitate the ablation of PMAT[4]. More recently, the VENUS trial has reported the benefit of EI-VOM in the treatment of persistent AF in addition to radiofrequency (RF) ablation[5]. However, in its post-hoc analysis, this benefit seems to be restricted to those with MI block[6]. In the present prospective study, we evaluated the effectiveness of an ‘upgraded 2C3L’ approach aiming to achieve a higher MI block rate, more thorough atrial compartmentation, and less AF/AT recurrence.