Disparities of Fibrillatory Electrogram Characteristics in Patients with Persistent and Long-Lasting Atrial Fibrillation

Introduction: The characteristics of electrogram morphology in different types of CAF were not fully elucidated in the previous literature. We quantify the organization of consecutive single bipolar electrograms by non-linear measurement as well as the conventional linear modalities. Methods: 19 persistent and 26 long-lasting AF patients (>1 year) underwent ablation were included. After PVI, 5335 segments (6 seconds of each) of intracardiac electrograms were acquired for linear-analysis, including dominant frequency, harmonic index, fractionation interval (NavX). Non-linear similarity index was used to quantize the extent of repetitiveness over time of the single electrograms over 6-seconds. The similarity index detects local activity waveforms, compares the morphological likeness of all possible LAW pairs, and estimates the probability of finding similar waveforms in the analyzed recording. Results: In both groups, less temporal variation of fibrillation electrograms was observed in the maximal CFE (FI<60 msec), as compared to the variable CFE (FI=60-120 msec), and non-CFE sites (FI>120 msec, SI =0.54±0.09 vs. 0.51 ±0.10 vs. 0.43±0.12, respectively, P=0.02). Maximal CFEs sites of the LA in long-lasting AF patients were characterized by less beat-to-beat electrogram similarities (P=0.001), whereas the measurement of other linear modalities were similar between two groups. Conclusion: In long-lasting persistent AF, the fibrillation electrograms of the LA were less consistent temporally compared to persistent AF, suggesting that the assumptions based on the linear analysis (such as DF) may be inappropriate to characterize the fibrillatory activities.