Study on the trustability of phase mapping methods to represent atrial potentials in atrial fibrillation

Phase Mapping (PhM) guides catheter ablation of long-standing rotors in atrial fibrillation (AF) by applying the Hilbert transform (HT) to electrogram (EGM) potential maps (PM). However, no stable rotors have been reported by other works with high density PM of the fibrillating human atria. This work studies how PhMs transform PMs due to preprocessing, interpolation and the application of the HT. A biophysical 3D model of the human atria simulated a 3.5 seconds AF episode with 5.594 EGM recordings. Three sets of PhMs were generated: a) By direct application of the HT to PMs; b) Achieving high-density by the interpolation of a simulated 64 poles basket catheter; c) preprocessing the basket catheter with low-pass filtering at 30 Hz and 2 Hz band-pass filtering centered on the dominant frequency. PhMs from a rotor location were compared with their corresponding PMs through the Earth Mover's Distance algorithm. An average concordance of 89.26%±6.24% was obtained for case a), lowering down to 72.26%±11.24% for case b) and being 34.43%±7.81% for case c). Hence, PhMs may notably transform real PMs creating fibrillatory activity that may not be observed in high-density potential maps.