Background: Extensive ablation in addition to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF) has not yielded consistent results, indicating diversity in their efficacy. Mitral regurgitation (MR) associated with AF may indicate a higher prevalence of arrhythmogenic substrate, suggesting potential benefits of extensive ablation for these patients., Methods: This post-hoc analysis of the EARNEST-PVI trial compared PVI alone versus an extensive ablation strategy (PVI-plus) in persistent AF patients, stratified by MR presence. The primary endpoint of the study was the recurrence of AF. The secondary endpoints included death, cerebral infarction, and procedure-related complications., Results: The trial included 495 eligible patients divided into MR and non-MR groups. The MR group consisted of 192 patients (89 in the PVI-alone arm and 103 in the PVI-plus arm), while the non-MR group had 303 patients (158 in the PVI-alone arm and 145 in the PVI-plus arm). In the non-MR group, recurrence rates were similar between PVI-alone and PVI-plus arms (Log-rank P = 0.47, Hazard ratio = 0.85 [95%CI: 0.54-1.33], P = 0.472). However, in the MR group, PVI-plus was significantly more effective in preventing AF recurrence (Log-rank P = 0.0014, Hazard ratio = 0.40 [95%CI: 0.22-0.72], P = 0.0021). No significant differences were observed in secondary endpoints between the two arms., Conclusions: For persistent AF patients with mild or greater MR, receiving PVI-plus was superior to PVI-alone in preventing AF recurrence. Conversely, for patients without MR, the effectiveness of extensive ablation was not demonstrated. These findings suggest tailoring ablation strategies based on MR presence can lead to better outcomes in AF management., Competing Interests: Declaration of competing interest Y. Sotomi has received grants from Roche Diagnostics, FUJIFILM Toyama Chemical, TOA EIYO, Bristol-Myers Squibb, Biosense Webster, Abbott Medical Japan, and NIPRO, and personal fees from Abiomed, Abbott Medical Japan, AstraZeneca, Amgen Astellas BioPharma, Biosensors, Boehringer Ingelheim, Bristol-Myers Squibb, Boston Scientific Japan, Bayer, Daiichi Sankyo, Eli Lilly, Novartis, TERUMO, Medtronic, and Pfizer Pharmaceuticals. S. Hikoso has received grants from Roche Diagnostics, FUJIFILM Toyama Chemical, Actelion Pharmaceuticals; and personal fees from AstraZeneca, Daiichi Sankyo, Astellas Pharma, Bayer, Pfizer Pharmaceuticals, Boehringer Ingelheim Japan, Kowa Company, and Ono Pharmaceutical. D. Nakatani has received personal fees from Roche Diagnostics. T. Dohi has received grants from Medtronic, Johnson & Johnson, and Abbott, during the conduct of the study. A. Sunaga has received grants from Medtronic, Johnson & Johnson, and Abbott, during the conduct of the study and personal fees from Bayer, Daiichi Sankyo, and Medtronic, outside the submitted work. M. Masuda has received personal fees from Bayer, Bristol-Myers Squibb, Boehringer Ingelheim, Daiichi Sankyo, Johnson & Johnson, Boston Scientific, Abbott, Nihon Kohden, Otsuka Pharmaceutical, AstraZeneca, and Medtronic, outside the submitted work. T. Watanabe has received personal fees from Biosense Webster, Abbott, Bristol-Myers Squibb, Pfizer, Boehringer Ingelheim, Bayer, Daiichi Sankyo, Nihon Kohden, and Fukuda Denshi, outside the submitted work. H. Minamiguchi has received grants from Medtronic, Johnson & Johnson, and Abbott, during the conduct of the study, and personal fees from Medtronic, Abbott, Johnson & Johnson, Nihon Kohden, Biotronik, Japan Lifeline, Daiichi Sankyo, Bayer, Pfizer, Squibb, Boehringer Ingelheim, Kowa, Ono Pharmaceutical, and Otsuka Pharmaceutical, outside the submitted work. Y. Egami has received personal fees from Japan Lifeline and Medtronic, and non-financial support from Johnson & Johnson, Abbott, and Medtronic, outside the submitted work; T. Oka has received personal fees from Medtronic, Biotronik, Abbott, Daiichi Sankyo, Beyer, Bristol-Myers Squibb, Boehringer Ingelheim, MSD, and AstraZeneca, outside the submitted work. Y. Matsuda has received personal fees from Daiichi Sankyo, Boehringer Ingelheim, Bayer, Medtronic, Boston Scientific Japan, Japan Lifeline, Asahi Kasei ZOLL Medical, Synaptic Medical Japan and Biotronik, outside the submitted work. M. Kawasaki has received personal fees from Medtronic, Bayer, Boehringer Ingelheim, Daiichi Sankyo, Bristol-Myers Squibb, and Abbott, and grants from Osaka Heart Club, outside the submitted work. K. Inoue has received personal fees from Bayer, Bristol-Myers Squibb, Boehringer Ingelheim, Daiichi Sankyo, Johnson & Johnson, and Medtronic, outside the submitted work. Y. Sakata has received personal fees from Otsuka Pharmaceutical, Ono Pharmaceutical, Daiichi Sankyo, Mitsubishi Tanabe Pharma Corporation, AstraZeneca K.K. and Actelion Pharmaceuticals, and grants from Roche Diagnostic, FUJIFILM Toyama Chemical, Bristol-Myers Squibb, Co, Biosense Webster, Inc., Abbott Medical Japan, Otsuka Pharmaceutical, Daiichi Sankyo Company, Mitsubishi Tanabe Pharma Corporation, Astellas Pharma, Kowa Company, Boehringer Ingelheim Japan, and Biotronik. Other authors have nothing to disclose., (Copyright © 2023. Published by Elsevier B.V.)