Figure 9. Comparison of the relationships between the APD restitution gradient and the magnitude of APD alternans taken from previous reports (Matthews et al. 2012) and between the λ ′ restitution gradient and the magnitude of λ ′ alternans.

This demonstrates that between a gradient of 0 and m_max for either function the λ′ restitution offers a better concordance with (A), and a smaller discrepancy from (B), the equality line (y=x). In contrast, the APD alternans rapidly diverges away from (A), and gives a larger discrepancy from (B), the equality line, excluding a direct relationship.