Figure 1. Comparison between SF_m and enhanced SF_m2 formulation of the safety factor.

Excitation waves were generated in an isotropic tissue stimulated with a 0.5(white colored) at the center of the tissue. A and B: Activation sequences are represented by isochrones (black lines, numbers indicate the instant of activation in ms) and the safety factor computed using SF_m (A) and SF_m2 (B) is color-coded. Tissue boundaries were not shown for the sake of clarity. C: SF_m (blue lines) and SF_m2 (green lines) as a function of the angular coordinate along the wavefront in the control tissue at four instants, 1 ms, 1.5 ms, 2 ms and 4 ms after the onset of the simulation. D: Evolution of the SF_m (blue lines) and SF_m2 (green lines) with distance to the center of the electrode in the diagonal and in the horizontal axis of the tissue (see white lines in Figure 1B). The evolution of the SF_2m with distance to the center of the electrode in the diagonal of the tissue stimulated with a 1.5 mm radius circular shaped electrode has also been included (red lines).