Aims: This study aims to improve atrial substrate characterization in atrial fibrillation (AF) by identifying electrophysiological characteristics associated with AF recurrence (AFR) after pulmonary vein isolation (PVI) to support prediction and guide personalized treatment.
Methods: We analyzed preablation electroanatomical maps and EGM recordings from 45 AF patients undergoing their first PVI at Hospital Clínico Universitario Lozano Blesa. Six of these patients experienced AF recurrence within 12 months. High-density maps were obtained using the Rhythmia system and the ORION basket catheter. For localized analysis, each atrial mesh was divided into 40 to 100 regions using the K-means clustering algorithm. The medians of seven EGM markers were calculated for each region: peak-to-peak voltage (Vpp); fractionation index; intra-region EGM similarity; and four Principal Components Analysis-based metrics that describe EGM complexity.
Results: Results are reported for 90 regions, as similar values were found in all cases. Patients with AFR showed lower voltages (0.98 vs 1.8), higher fractionation (9.29 vs 5.45), and greater EGM variability (0.53 vs 0.61), indicating structural remodeling and conduction abnormalities. PCA markers further revealed lower variance explained by the first component (r_sigma^1: 55.71 vs 70.78) and a higher number of components needed to reach 90% of the variance (20.25 vs 12), suggesting increased signal heterogeneity and atrial disorganization.
Conclusions: This study demonstrates that both conventional EGM markers and PCA-derived indices based on local EGM morphology and complexity can effectively distinguish between patients with and without AFR after PVI.