Figure 7. Spatially heterogeneous parasympathetic activity in the setting of high sympathetic activity leads to wave break and reentry in a computational model.

(A) Snapshots of the membrane voltage when the 2-D tissue is paced at the left edge at CL = 300 ms. Times shown are measured after the 21st paced beat. Model parameters are [ACh] = 1 × 10^–2 μmol/l and p_b = 0.45 to simulate high sympathetic and parasympathetic activity. Voltage trace shown is for a cell located at l_x = 80 and l_y = 80. (B) Same simulation with heterogeneous distribution of [ACh] proportional to the experimentally measured parasympathetic fiber counts. Times shown are measured after the 27th paced beat.