Supplemental Table 1. Echocardiography of DN-MSTN TG13 Mice.

Echocardiography measurements performed using M-mode, parasternal short axis at mid-papillary muscle level, on DN-MSTN TG13 mice and WT littermates (N=4, each group) demonstrates no significant differences in LV systolic function as assessed by fractional shortening. Data presented are mean ± standard deviation. None of the parameters reached statistical significance, although heart rate displayed a non-significant trend (p = 0.06). See Methods section for details of analysis. HR = Heart rate, IVS = intraventricular septum thickness, LVPW = left ventricular posterior wall thickness, LVD Diastolic = Left ventricular dimension in diastole, LVD systolic = Left ventricular dimension in systole, FS = fractional shortening.

	DN-MSTN TG13 (N = 4)	WT (N=4)	P
HR (bpm)	554 ± 122	697 ± 27	NS
IVS (mm)	0.91 ± 0.17	0.93 ± 0.19	NS
LVPW (mm)	1.25 ± 0.27	1.37 ± 0.18	NS
LVD Diastolic (mm)	3.00 ± 0.34	3.05 ± 0.07	NS
LVD Systolic (mm)	1.14 ± 0.13	1.23 ± 0.26	NS
FS (%)	62.11 ± 1.24	59.56 ± 2.89	NS