Figure 7. EHTs seeded with human-derived cardiomyocytes.

(a) Laser-cut decellularized myocardium serves as a viable scaffold for several cardiomyocyte sources, including neonatal rats, human embryonic stem cells (hESCs), and human induced pluripotent stem cells (hiPSCs). (b) A representative trace showing simultaneous acquisition of intracellular Ca²⁺ (fura-2 fluorescence) and isometric twitch tension measured in an EHT containing hESC-derived cardiomyocytes. (c) A representative twitch trace recorded in an EHT containing hiPSC-derived cardiomyocytes. The twitch is superimposed on a twitch produced by a human right ventricular trabecula, digitized from Nejad et al.⁵⁷ (d) Mean twitch kinetic parameters and peak tension measured in hiPSC-EHTs (n = 8). Gray bars indicate mean properties reported for human left ventricular muscle strips by Mulieri et al.⁵⁸. Abbreviations: TTP, time to peak stress; RT50, time from peak to 50% relaxation.