Electrogram morphology recurrence patterns during atrial fibrillation

Background: Traditional mapping of atrial fibrillati on (AF) is limited by changing electrogram morphologies and variable cycle lengths. Objective: We tested the hypothesis that morphology recurrence plot analysis would identify sites of stable and repeatable electro-gram morphology patterns. Methods: AF electrograms recorded from left atrial (LA) and right atrial (RA) sites in 19 patients (10 men; mean age 59 ± 10 years) before AF ablation were analyzed. Morphology recurrence plots for each electrogram recording were created by cross-correlation of each automatically detected activation with every other activation in the recording. A recurrence percentage, the percentage of the most common morphology, and the mean cycle length of activations with the most recurrent morphology were computed. Results: The morphology recurrence plots commonly showed checkerboard patterns of alternating high and low cross-correlation values, indicating periodic recurrences in morphologies. The mean recurrence percentage for all sites and all patients was 38 ± 25%. The highest recurrence percentage per patient averaged 83 ± 17%. The highest recurrence percentage was located in the RA in 5 patients and in the LA in 14 patients. Patients with sites of shortest mean cycle length of activations with the most recurrent morphology in the LA and RA had ablation failure rates of 25% and 100%, respectively (hazard ratio 4.95; P = .05). Conclusion: A new technique to characterize electrogram morphology recurrence demonstrated that there is a distribution of sites with high and low repeatability of electrogram morphologies. Sites with rapid activation of highly repetitive morphology patterns may be critical to sustaining AF. Further testing of this approach to map and ablate AF sources is warranted.