Fig. 6: Maturation status of iPSC-CMs affects their drug response.

a Schematic diagram of FP traces showing how the data was analysed. b Quantitative analysis of the effect of verapamil on spike amplitude. n = 17 (B27, MM) and 18 (MM + NP, MM + NP + ES) cultures derived from 3 independent experiments using 2 iPSC lines. Experimental design is shown in Supplementary Fig. 4. c Representative averaged field potential (FP) traces of verapamil-treated iPSC-CMs showing the FPDc (FP duration corrected by Fridericia’s formula) shortening. d Quantitative analysis of the effect of verapamil on FPDc shortening (ΔΔFPDc). n = 17 (B27, MM) and 18 (MM + NP, MM + NP + ES) cultures derived from 3 independent experiments using 2 iPSC lines. e Representative traces illustrating the FPDc prolongation induced by increasing concentrations of E-4031. f Quantitative analysis of the effect of E-4031 on FPDc. n = 10 (B27), 12 (MM), and 11 (MM + NP, MM + NP + ES) cultures from 2 independent experiments. g, h Quantitative analysis of concentration-dependent effect of isoprenaline on FPDc (g) and beating rate (h). n = 18 (B27), 23 (MM, MM + NP), and 24 (MM + NP + ES) cultures derived from 3 (B27) or 4 (MM, MM + NP, MM + NP + ES) independent experiments of 2 iPSC lines. Data are normalised to the respective baseline of each group (b, d, f, g, h). Symbols in (b, d, f, g) denote iPSC lines: circles for isWT7, and squares for iWTD2. Source data are provided as a Source Data file. Statistical analysis using two-way ANOVA with Dunnett’s post-test. Data are presented as mean ± 95% CI (h) and in box plots indicating median (middle line), 25th, 75th percentile (box) and min and max data points (whiskers) in (b, d, f, g).