Analysis of the relative contribution of varying APD, vmin, and slope (with respect to their deterministic values) to the mean IBI. (Black) Reference simulation curve. (Cyan graph) Mean IBI was calculated from the three major determinants using Eq. 28. (Red, green, and blue graphs) Only one determinant was free to vary due to stochasticity (slope, vmin, and APD for the red, green, and blue graphs, respectively), while the other two were fixed to their deterministic value. To see this figure in color, go online.