Submitted on April 24, 2009
Revised on June 22, 2009
Accepted on June 23, 2009
Speckle Tracking Echocardiography in the Assessment of Mouse Models of Cardiac Dysfunction
Yu Peng, Zoran B Popovic1*, Nikolai Sopko, Jeannie Drinko, Zheng zhang, James D. Thomas1, and Marc S Penn1
1 Cleveland Clinic Foundation
* To whom correspondence should be addressed. E-mail: popoviz{at}ccf.org.
Two-dimensional (2D) speckle tracking echocardiography (STE) accurately quantifies circumferential strain (Scirc) and radial strain (Srad) in humans and large animals. This study was performed to assess sensitivity of Scirc and Srad to left ventricular (LV) dysfunction in mouse models. We performed 2D and M-mode echocardiography: 1) in 6 mice during superficial- and profound isoflurane anesthesia; 2) serially in 12 mice to monitor development of heart failure induced by transverse aortic constriction (TAC) and 8 corresponding controls; and 3) in 26 mice with varying degree of TAC-induced heart failure and 12 corresponding controls immediately prior their sacrifice. Fractional shortening (FSH) and LV mass were measured from standard M-mode tracings, while Scirc and Srad were derived by STE. Percent fibrosis and myocyte diameters were assessed from whole-heart cross-sectional specimens stained by Masson trichrome. Profound isoflurane anesthesia decreased Scirc (p=0.027) but not Srad (p>0.05). Mice subjected to TAC showed immediate and sustained decrease in FSH (p= 0.035), Scirc (p=0.016) and Srad (p=0.012). Scirc showed better correlation with FSH (r=0.56, P<0.0001) and LV mass (r=0.42, p = 0.0003) than Srad (r=0.54, p<0.0001 and r=0.37, p=0.014 for FSH and LV mass, respectively). Percent fibrosis correlated better with Scirc (r=0.46 p=0.004) than with Srad (r=-0.32, p=0.05), while myocyte diameter showed similar correlation with both strains (r=0.45 and r=-0.44, respectively, p=0.006 for both). STE correctly identifies LV dysfunction and histological changes in mice and can be used for serial assessment of cardiac remodeling in murine models.
