Echocardiographic endpoints were compared between FS3KO and Smad3 fl/fl mice at baseline and 4–8 weeks after tamoxifen injection. Male and female FS3KO mice had comparable LVEF, LVEDV, LVESV, and end-diastolic left ventricular anterior and posterior wall thickness with corresponding Smad3 fl/fl controls (A–J). Dimensions of the ascending aorta (K–L) and heart rate (M–N) were also comparable between groups. Tissue Doppler imaging showed that FS3KO mice and corresponding Smad3 fl/fl controls had comparable E/E’ ratio, suggesting that fibroblast-specific Smad3 loss does not significantly affect baseline diastolic function (O–P). Sample size: Smad3 fl/fl (male, n=11; female, n=9), FS3KO mice (male, n=11; female, n=10). ANOVA followed by Sidak’s multiple comparisons test.