Assessment of left ventricular mass in mice: comparison between two-dimensional and m-mode echocardiography.
OBJECTIVE
M-mode echocardiography has been used extensively for estimating left ventricular (LV) mass in mice, but accuracy is limited by its unidimensional nature. This study tested whether two-dimensional (2-D) echocardiographic measurement of LV mass using area-length and truncated ellipsoid methods overcomes this limitation.


METHODS
Twenty-five anesthetized FVB/N mice (Mus musculus) underwent high resolution (15 MHZ) two-dimensionally directed M-mode and 2-D echocardiography. End-diastolic epicardial and endocardial areas from short-axis views and the LV orthogonal long-axis views were measured, while LV mass was calculated by 2-D area-length and truncated ellipsoid methods. LV mass was calculated from M-mode using the uncorrected cube equation. Hearts were removed and weighed after completing the echocardiographic studies. The correlation and agreement between echocardiographic-determined LV mass and gravimetric LV weight were examined.


RESULTS
LV mass using the area-length method correlated better with autopsy LV weight (r = 0.87, slope = 0.87, standard error of the estimate [SEE] = 12.4 mg, P < 0.001) than M-mode echocardiography (r = 0.85, slope = 0.71, SEE = 11.1 mg, P < 0.001), and the degree of agreement (bias +/- 2 SD) was better (10.2 +/- 25.1 mg vs 13.1 +/- 25.8 mg, P = NS). Although 2-D truncated ellipsoid LV mass showed a good correlation with necropsy LV weight (r = 0.87, slope = 0.78, SEE = 11.0 mg, P < 0.001), the agreement between the truncated ellipsoid estimates and LV weight was less than that between M-mode and gravimetric LV mass.


CONCLUSIONS
The 2-D area-length method is an accurate method of LV mass determination in symmetrical ventricles and can be used as an alternative for in vivo measurement of LV mass in mice.
Kiatchoosakun
Songsak
S
Department of Medicine, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44106-5038, USA.
Restivo
Joseph
J
Kirkpatrick
Darryl
D
Hoit
Brian D
BD
D000818:Animals; D004452:Echocardiography / Q000706:statistics & numerical data; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008297:Male; D051379:Mice; D015588:Observer Variation