Complete vs. incomplete low-voltage area ablation in persistent atrial fibrillation: implications for arrhythmia recurrence

Low-voltage area (LVA) ablation is one of the therapeutic options for patients with persistent atrial fibrillation (AF) who are refractory to conventional treatments. However, in some cases, complete elimination of LVAs is challenging due to the risk of damage to the esophagus and physiological conduction system, as well as the presence of excessively extensive LVAs. It has not been clear whether incomplete LVA ablation increased the risk of arrhythmia recurrence.

This study is a post-hoc sub-analysis of the multicenter randomized controlled trial SUPPRESS AF. In the SUPPRESS AF trial, patients with persistent AF were randomly assigned in a 1:1 ratio to undergo LVA ablation or not if their left atrial LVAs covered ≥5 cm² on a voltage map after pulmonary vein isolation. The primary endpoint was freedom from AF/atrial tachycardia (AT) recurrence, monitored using 24-hour Holter ECGs and twice-daily portable ECG recordings, without antiarrhythmic drugs during the 1-year follow-up period after the initial ablation. In the present study, clinical outcomes were compared among three groups: no LVA ablation, complete LVA ablation, and incomplete LVA ablation.

Among the 341 patients included, 170 underwent LVA ablation, with 37 cases remaining incomplete. The LVA non-complete group had significantly larger LVAs compared to the no LVA and LVA complete groups (22.0 [12.9, 36.0] cm² vs. 14.0 [8.7, 24.3] cm² and 12.2 [8.1, 19.0] cm², respectively; p=0.005, Table). Reasons for incomplete LVA ablation included concerns about damage to the esophagus and the physiological conduction system (including the His bundle and anterior transverse conduction) in 29 patients, excessive breadth of the LVA in 4 patients, and inability to manipulate the ablation catheter to some LVAs in 4 patients. Arrhythmia-free survival was comparable among the three groups (Figure). However, arrhythmia recurrence with AT forms was more frequently observed in the complete LVA ablation group than the no LVA ablation group (Figure).

This post-hoc sub-analysis of a randomized controlled trial did not identify any clear disadvantages of incomplete LVA ablation. Complete LVA ablation may be associated with an increased risk of AT recurrence. These results highlighted the lack of satisfactory understanding of the LVA ablation procedure.TableFigure