Fig. 5.
Bifurcation diagrams for action potential duration (APD; A, C, and E) and sensitivity of APD alternans-normalized magnitude (APD-ANM; B, D, and F) as functions of chronic atrial fibrillation (cAF)-induced myofilament remodeling in simulations with our right atrial (RA; blue lines) and left atrial (LA; green lines) electromechanical models with human chronic atrial fibrillation (cAF)-induced ionic remodeling and a sarcomere length (SL) of 1.9 µm. To incorporate cAF-induced increased thin filament activation, each unique simulation has a cAF-remodeled value of kon (A and B), koffH (C and D), or perm50 (E and F) ranging from normal (100% of control) to diseased (300% of control for kon and 20% of control for koffH and perm50). The pink dashed lines in B, D, and F indicate the division between subthreshold ANM and significant ANM (>5%). AF, atrial fibrillation.