Fig. 2.

Contraction kinetics are slowed in SMA cardiomyocytes. a Representative recordings of sarcomere length obtained from ventricular myocytes isolated from unaffected or SMA mice (aged P12–13). Cells were field stimulated to contract at 1 Hz. Fractional shortening was not markedly different; however, there was a significant decrease in the diastolic sarcomere length. b Shown are normalized average record of a typical single twitch illustrating the slowed contraction and relaxation kinetics in SMA compared to control cardiomyocytes. Both the time to peak shortening and time to 50% relaxation (T₅₀) were significantly increased in SMA myocytes compared to control Statistical analysis: p values shown for t test, n = 36 and 37 for SMA and control, respectively