Fig. 1: Differentiation and characterization of the human embryonic stem cells derived ventricular and atrial cardiomyocytes.

a Schematic representation of the human embryonic stem cells (hESC) differentiation protocols used to derive ventricular (blue) or atrial (red) cardiomyocytes. b, c Representative flow-cytometric analyses of the proportion of NKX2.5⁺/cTnT⁺ cells (left panels) and the proportion of MLC2V⁺ cells among these NKX2.5⁺/cTnT⁺ cells (right panels) in day 20 HES3-NKX2–5^gfp/w EBs using either the ventricular (b) or the atrial (c) differentiation protocols. Note that using the ventricular and atrial differentiation protocols ~1% and ~5% of the differentiating cells, respectively, were TnT⁺/Nkx2.5⁻ cells (sinoatrial node like cells) and that among the differentiating cTnT⁺/NKX2.5⁺ cells obtained ~71% and ~3%, respectively, were MLC2v positive. d Patch–clamp action potential (AP) recordings of hESC-derived ventricular (left tracing) and atrial (right tracing) cells during 1 Hz field stimulation. e Summary of AP duration (APD) measurements from hESC-derived ventricular (blue) and atrial (red) cells (values are expressed as mean ± SEM). Note that hESC-derived atrial cardiomyocytes (n = 17, biologically independent cells) displayed shorter APD₃₀, APD₅₀, and APD₉₀ values and decreased phase 0 maximal upstroke velocity compared with the ventricular cells (n = 13, biologically independent cells). Recordings were performed at 1 Hz stimulation frequency of. **p < 0.01, ****p < 0.0001, unpaired t test is used for comparison.