Ca²⁺ transient kinetics in WT and cMyBP-C^−/− mECT. (A) Amplitude-normalized twitch force (TF; dashed lines) and Ca²⁺ transient (solid lines) in WT and cMyBP-C^−/− mECT paced at 6 Hz. (B) Amplitude-normalized Ca²⁺ transients in vehicle (solid lines)- and dobutamine-treated (dashed lines) WT and cMyBP-C^−/− mECT paced at 6 Hz. (C) Amplitude-normalized Ca²⁺ transients in WT and cMyBP-C^−/− mECT paced at 6 (solid lines) and 9 Hz (dashed lines). Blue lines (solid and dashed) show WT mECT, and red lines (solid and dashed) show cMyBP-C^−/− mECT. (A–C) Error bars indicate SEM. AU, arbitrary units.