Figure 10: Borders in parameter space between stable physiologic conditions, above, and unstable physiologic conditions, below, the data points for 4 different models with varying complexity in the radial dimension of muscle thickness. On-off denotes Purkinje fiber action with no endo-to-epicardial gradients. Off-on denotes no Purkinje fiber action with endo-to-epicardial gradients. On-on denotes both Purkinje fiber action and endo-to-epicardial gradients. Off-off denotes neither refinement.