Fig. 7

Bifurcation Diagram of Full AP System with PCL as Continuation Parameter. A Bifurcation diagram of model PV with the pacing cycling length PCL as the continuation parameter. Here, the channel conductance G _K , the current step amplitude A and the step duration d were chosen as for Fig. 1PV. The red dashed and solid lines show the maximum and minimum voltage values of unstable and stable limit cycles. Blue markers depict several PD bifurcations of limit cycles spread across a wide range of PCL values. B Zoom into the PD area of A) in neighborhood of the PCL value corresponding to the chaotic EAD trace shown in Fig. 1PV. Again, the detection of serveral PD bifurcations that seem to obey Eq. (11) suggests that the period doubling route to chaotic EADs is on hand. The upper solid branch depicts the minimum voltage value of stable limit cycles that correspond to regular periodic AP orbits, once again demonstrating the coexistence of chaotic EAD dynamics and periodic AP dynamics in model PV