Figure 7.

Effect of Ca²⁺ sensitization on Ca²⁺ sparks in atrial iPSC-CMs with reduced (si-cTnC) cTnC levels. A, Representative confocal line scans of atrial iPSC-CMs with normal (control, siRNA ns) and reduced (si-cTnC, siRNA cTnC) cTnC levels, pretreated with EMD57033 (EMD, 5 µmol/L). B, Mean±SEM Ca²⁺ spark frequency (CaSpF, left) and amplitude (right). *P<0.05, **P<0.01 vs control and si-cTnC. n=number of myocytes (2 differentiations). Comparison was made using the Kruskal-Wallis test followed by the Dunn post hoc test. Ctrl indicates control; cTnC, cardiac troponin C; iPSC-CM, induced pluripotent stem cell–derived cardiac myocyte; ns, nonsilencing; and siRNA, small interfering RNA.