Aims: This study investigates the feasibility of omnipolar technique (OT), applied in sequential mapping during electrophysiological procedures, without using specialized catheter geometries using numerical simulations. Specifically, we assess the usage of OT with multiple bipolar recordings measured randomly around a point of interest and quantify the effect of different displacements on the wavefront direction (WD) and omnipolar voltage (OV).
Methods: We simulated a 2D atrial slab with areas of different conduction velocities. The extracellular electrical potential and the transmembrane voltage were obtained solving the bidomain equations using openCARP. For each point of interest, three concentric circles of radius r = 0.5, 1, 2 mm were defined. Within each circle, we randomly selected M = 3, 5, 10, 20 bipolar measurements with an interelectrode distance of 1 mm. The local electrical field is then estimated applying OT on bipolar measurements, from which WD and OV are derived. The reference WD was computed as the normalized gradient of the local activation time map. Based on reference WD, a bipolar voltage map was generated, measuring the voltage in the WD. We used this as reference for OV.
Results: The mean absolute error (MAE) of the estimated WD decreased with smaller radii and increasing number of bipolar recordings. The largest error was 32.82°, obtained with M = 3 and r = 2mm. For r = 0.5 mm, the WD MAE was < 8°. Regarding the OV, unexpectedly, the minimum MAE of 0.21 mV was obtained for r = 1mm and M = 10.
Conclusions: With increasing r the WD and OV deviated substantially from reference values. A possible explanation can be the time misalignment between bipolar recordings measured within bigger areas. In conclusion, OT is effective in estimating the WD and OV when several bipolar recordings are available within a small area.