Ultra-high resolution for accurate analysis in cardiac mapping: a path towards fulfillment of assumptions in...

Omnipolar technology has improved the characterisation of complex arrhythmias by enabling more accurate, direction-independent electrogram analysis. Omnipolar EGMs are reconstructed assuming locally planar and homogeneous propagation. However, anatomical complexity, electrode spacing, tissue heterogeneity, or poor catheter contact may violate this assumption. This study aims to quantify the extent to which key assumptions are fulfilled in clinical settings by analysing amplitude and morphology variability, as well as wavefront non-planarity. Additionally, we evaluate how such deviations affect the accuracy of omnipolar EGM reconstruction and propagation direction estimation. To enhance performance, we introduce the concept of Ultra-High Resolution-defined as the resolution required to meet these assumptions-and propose electrical field interpolation as a method to bridge this target with feasible interelectrode spacing in practical devices. Results are validated using in silico simulations and clinical recordings acquired with the Advisor™ HD Grid Mapping Catheter. The results show that at 4 mm interelectrode spacing-common in current catheters-deviations from the underlying assumptions are frequent, leading to inaccurate omnipolar signal computation and derived parameters. The proposed Ultra-High Resolution proves reliable, as evidenced by low normalised root mean square error and high Pearson correlation of the interpolated unipolar signals. By effectively reducing interelectrode spacing through interpolation, compliance with the underlying assumptions improves significantly. Accurate omnipolar mapping requires tighter interelectrode spacing than current catheters provide. We show that interpolation reliably enhances spatial resolution, enabling assumption compliance without hardware changes. A spacing of 0.5 mm defines Ultra-High Resolution, beyond which further gains are negligible. We establish a practical benchmark for future catheter design and signal processing.