Echocardiographic evaluation of cardiac function. (A) Representative M-mode echocardiography from wild-type (Clcn3+/+; left) and heart-specific ClC-3 knockout (hsClcn3−/−; right) mice. (B) Echocardiographic measurements in Clcn3+/+ and hsClcn3−/− mice. IVSd, interventricular septum thickness at the end of diastole; LVDd, left ventricular (LV) dimension at the end of diastole; LVPWd, LV posterior wall thickness at the end of diastole; IVSs, interventricular septum thickness at the end of systole; LVDs, LV dimension at the end of systole; LVPWs, LV posterior wall thickness at the end of systole; LVEP, calculated LV ejection fraction; %FS, LV fractional shortening; estimated LV mass, LVM (mg) = 1.05[(IVS + LVID + LVPW)3 − (LVID)3], where 1.05 is the specific gravity of the myocardium. *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with Clcn3+/+ mice. C. Single longitudinal section (μm) of hearts to demonstrate all four heart chambers. Longitudinal were stained with hematoxylin and eosin (Bar = 2 mm) (Duan D. et al. unpublished data.)