Electrogram Fractionation Metrics in Spatio-Temporal Dispersion Based Catheter Ablation of Persistent Atrial Fibrillation

Atrial fibrillation (AF) is a common heart condition in the elderly, significantly increasing stroke risk and posing a public health concern. Among treatments, catheter ablation (CA) is the most effective long-term solution for persistent AF. A new CA technique targets spatio-temporal dispersion (STD) patterns in intracardiac electrograms (EGMs), specifically aiming at active zones sustaining arrhythmia. Some cardiologists also target fractionated electrograms for ablation. However, the relationship between fragmentation and STD patterns is not well understood, leading to expert disagreement. Current literature lacks comparisons of quantitative fragmentation metrics with STD presence. To address this issue, the present contribution puts forward and explores various metrics to measure fragmentation of EGM signals. Metrics include Shannon entropy, normalized variance, normalized mean absolute difference, percentage of alternating segments and zero crossings. They are evaluated on real EGM data from 53 patients with persistent AF, labeled by experts from Nice Pasteur University Hospital. Results indicate that fragmentation can occur regardless of the time or space delay between catheter poles. This study highlights the importance of statistical and signal processing methods in understanding how fragmentation relates to STD patterns in EGMs, enhancing knowledge of STD mechanisms and refining treatment strategies for AF.