Transthoracic echocardiography in models of cardiac disease in the mouse.
BACKGROUND
Transthoracic echocardiography (M-mode and Doppler) offers a noninvasive approach for in vivo evaluation of the mouse heart. The present study examines its usefulness for assessing the morphological/functional phenotype of the left ventricle (LV) in several transgenic and surgical murine models of cardiac disease.


RESULTS
Observations were made in 83 intact, anesthetized mice. In mice with a surgical arteriovenous fistula, volume overload and LV dilation were detected. In normal mice, echocardiographic indexes of increased contractility (dobutamine) were confirmed by LV dP/dtmax. In transgenic mice with overexpression of the beta 2-adrenergic receptor, heart rate and mean velocity of circumferential fiber shortening were increased, indicating enhanced contractility. In colony screening of transgenic mice overexpressing the H-ras gene, 45% had increased LV wall thickness (> 0.9 mm), and those showing a striking increase were selected for breeding. In mice with LV hypertrophy (aortic constriction) and normal mice, the actual LV mass determined by echocardiography correlated well (r = .93), and 95% confidence limits were determined. The maximum intraobserver and interobserver coefficients of variation for M-mode data were 0.03 +/- 0.29 mm (+/- 2 SD), < 10% for LV internal dimensions but 27% to 30% for wall thickness.


CONCLUSIONS
These studies provide the first application of transthoracic echocardiography for morphological/functional characterization of the cardiac phenotype in transgenic and surgical murine models, including (1) high reliability for detecting LV chamber dilation and function; (2) reliability (and its limits) for determining abnormal LV wall thickness and LV mass; (3) identification of marked, sometimes asymmetrical, hypertrophy in a transgenic model of hypertrophic cardiomyopathy; and (4) usefulness for transgenic colony screening to identify markedly abnormal phenotypes.
Tanaka
N
N
Department of Medicine, University of California at San Diego, La Jolla 92093-0613, USA.
Dalton
N
N
Mao
L
L
Rockman
H A
HA
Peterson
K L
KL
Gottshall
K R
KR
Hunter
J J
JJ
Chien
K R
KR
Ross
J
J
D000758:Anesthesia; D000818:Animals; D004280:Dobutamine / Q000494:pharmacology; D004452:Echocardiography; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D015203:Reproducibility of Results; D016277:Ventricular Function, Left
D004280:Dobutamine