Abstract 1071: Two-Dimensional Strain Imaging Correctly Identifies and Characterizes Left Ventricular Dysfunction in a Mouse Model of Pressure Overload-Induced Heart Failure
Two-dimensional (2D) speckle tracking echocardiography (STE) accurately quantifies circumferential strains (Scirc) and radial strains (Srad) in humans. This study was performed to assess sensitivity of Scirc and Srad to pressure overload-induced left ventricular (LV) dysfunction and fibrosis. 2D echocardiographic LV short-axis images (14 MHz transducer, GE Vivid 7) were assessed in 12 mice with transverse aortic banding and 8 controls. Fractional shortening (FSH) and LV mass were measured from standard M mode tracings, while Scirc and Srad were derived by STE using Echopac PC software (GE Medical). Collagen density was assessed histologically with LV stained by Masson trichrome. We analyzed data obtained early (3 ± 2 days), mid-term (95 ± 44 days), and late (174 ± 73 days) after surgery. Aortic banding immediately decreased FSH (p = 0.035) Scirc (p = 0.016) and Srad (p = 0.012), which further worsened during follow-up (Fig. 1⇓). Scirc slopes showed better correlation with LV mass slopes (r = 0.88) and FSH slopes (r = −0.76) than Srad slopes (r = −0.55 and r = 0.61 for LV mass and FSH, respectively, p = 0.004 and p = 0.1 for absolute values for both vs. Scirc). LV mass was larger in banded mice (p = 0.01), with the difference between the two groups continuing to increase over time (p = 0.004). In 16 mice with histology data, worse systolic function by M mode echocardiography was associated with higher fibrosis percent (p = 0.008), lower Scirc (p = 0.006), and trend towards lower Srad (p = 0.09). STE correctly identifies pressure overload induced LV dysfunction and histology changes in mice and can be used for serial assessment of cardiac remodeling in murine studies.