Fig. 4.

Simulated APs of hPSC-CMs with different durations (180–290 ms) (A) and corresponding SPICE derived FPs (B). The relationship of the APD versus the FPD is shown in panel G. Simulated APD variation due to K⁺ current modulation (C) and corresponding SPICE derived FPs (D). The ADP₉₀-ADP₇₀ values plotted versus the FDP_4′-FDP_3′ are shown in panel H. Simulated APD variation without K⁺ current modulation (E) and corresponding SPICE derived FPs (F). The ADP₉₀-ADP₇₀ values plotted versus the FDP_4′-FDP_3′ are shown in panel I. (J) FPs measured from hPSC-CMs exposed to E-4031. E-4031 evoked changes in K⁺ current and FPD prolongation (L) and modulation of the FDP_4′-FDP_3′ (N). Bay K 8644 (K) induced prolongation (M) without modulation of the FDP_4′-FDP_3′ (O).