Integration of automated peak frequency annotation with voltage mapping for identifying ventricular tachycardia ablation sites.

BACKGROUND

Peak frequency (PF) analysis has emerged as a novel tool for identifying arrhythmogenic substrates in ventricular tachycardia (VT) ablation, particularly when combined with traditional substrate mapping techniques such as voltage mapping and Isochronal Late Activation Mapping (ILAM). This study evaluates the utility of PF analysis in scarred myocardial regions, with a focus on areas containing manually annotated late potentials (LPs).

METHODS

Electroanatomical mapping using the EnSite X™ system was performed in 20 patients undergoing VT ablation. PF analysis was applied to scarred regions with voltages < 1.5 mV, with and without LPs, to identify zones of high-frequency activity. PF zones (PFZs) were compared to voltage maps and ILAM to assess spatial correlation with deceleration zones (DZs) and their role in defining ablation targets.

RESULTS

Peak frequency distributions differed significantly across myocardium conditions (H = 254.92, p < 0.0001). The median peak frequency was 120.0 Hz (77.3-179.0 Hz) in normal voltage myocardium, 145.0 Hz (100.0-194.3 Hz) in low-voltage myocardium without LPs, and 291.0 Hz (190.3-380.3 Hz) in low-voltage myocardium with LPs. Pairwise comparisons showed significant differences: normal voltage vs. low voltage without LPs (U = 46,455.0; p = 0.0019), normal voltage vs. low voltage with LPs (U = 20,935.5; p < 0.0001), and low voltage without LPs vs. low voltage with LPs (U = 19,548.0; p < 0.0001). PFZs exhibited strong colocalization with DZs identified via ILAM, with > 50% spatial overlap in most cases. The automated peak frequency annotation algorithm demonstrated high reproducibility, significantly reducing operator dependency compared to manual annotation.

CONCLUSION

PF analysis provides a robust and reproducible method for identifying arrhythmogenic substrates in VT ablation. When integrated with voltage mapping and ILAM, it facilitates precise localization of critical ablation targets, particularly in regions with LPs. These findings highlight the potential of PF analysis to enhance the efficacy of substrate-based ablation strategies.