Calcium transient analysis in induced pluripotent stem cell-derived cardiomyocytes. (A) Representative recordings of Fura-2-AM fluorescence ratio at 340/380 nm excitation wavelengths and cell shortening. (B) Quantitative analysis of intracellullar calcium transient dynamics. R is the Fura 2-ratio at 340/360 nm. Rmax, maximal systolic calcium amplitude (the difference of R-systolic and R-diastolic); +dR/dt, maximal rate of fluorescence rise during sytole; −dR/dt, maximal rate of fluorescence decay during diastole; TTP50%, time to 50% peak (in ms); TTB50%, time to 50% baseline (ms). Data are means ± SEM, N = 35; cells studied in three independent experiments.