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.