Acute and long-term outcomes of pulmonary vein isolation and left atrial substrate modification for non-paroxysmal atrial fibrillation: a non-randomized trial

Background: The long-term success rate of nonparoxysmal atrial fibrillation (AF) treated with pulmonary vein isolation (PVI) alone is not ideal. This may indicate atrial fibrosis as a major cause of recurrence. Therefore, the aim of this study is to investigate the efficacy of left atrial substrate modification (LASM) by targeting low-voltage area. Methods: A total of 157 consecutive patients with drug-refractory nonparoxysmal AF who underwent radiofrequency ablation during hospitalization in the Third People's Hospital of Chengdu from April 2017 to August 2021 were prospectively included. Stepwise ablation was performed in two different orders: LASM first (n=53) and PVI first (n=104) group. All patients underwent ablation during AF, and the procedural endpoint was AF termination during ablation. In the LASM first group, LASM was performed first and if AF was terminated, PVI was not performed. Similarly, in the PVI first groups, LASM was performed if AF was not terminated. The primary outcome were AF termination and freedom from AF. The secondary outcome was adverse events. Cox regression analysis was used to define predictors of AF termination, and Kaplan-Meier analysis was used to assess differences between groups in AF freedom. Results: 6.7%; P>0.05). Conclusions: LASM provides higher immediate success and a slightly better long-term success rate compared to PVI. Patients who terminated AF were more likely to have AF freedom than those who did not. AF termination during procedure may improve symptoms and reduce hospitalization.