Aims Ablation for atrial fibrillation (AF) has been suggested to be associated with 'reverse left atrial remodelling'. Reduction in left atrial volume index (LAVIR) is regarded as a determinant of reverse remodelling following pulmonary vein isolation (PVI). However, there is paucity on data about the predictors for LAVIR after PVI. In this study, we aimed to investigate predictors of LAVIR at 12 months in AF patients undergoing cryoballoon-based PVI. Methods and results Patients with symptomatic paroxysmal or persistent AF despite ≥1 antiarrhythmic drug(s), who were scheduled for cryoballoon-based AF ablation procedure per the recent consensus recommendations, were enrolled and followed-up for 12 months in this prospective observational study. Left atrial volume was derived using the biplane area-length method. A total of 160 patients (54.25 ± 7.66 years, 44.40% female) were involved in the study. Reduction in left atrial volume index occurred in 120 patients. Age [hazard ratio (HR): 0.901, 95% confidence interval (CI): 0.828-0.981, P = 0.017], hypertension (HR: 0.151, 95% CI: 0.048-0.471, P = 0.001), mild mitral regurgitation (MR) (HR: 5.327, 95% CI: 1.489-19.058, P = 0.010), and AF recurrence (HR: 0.017, 95% CI: 0.005-0.065, P< 0.001) were found to be independent predictors for LAVIR. Conclusion To the best of our knowledge, this is the largest study in the literature investigating the predictors of LAVIR following AF ablation. According to this data, younger patients without hypertension or moderate MR are most likely to experience LAVIR following ablation. Published on behalf of the European Society of Cardiology. All rights reserved.