Doppler myocardial imaging in the diagnosis of early systolic left ventricular dysfunction in diabetic rats.
OBJECTIVE
To find out if Doppler myocardial imaging (DMI) can detect early signs of left ventricular (LV) dysfunction in a rat model of diabetic cardiomyopathy.


METHODS
Eight control and 12 Streptozotocin (STZ)-induced diabetic rats underwent transthoracic echocardiography with high-resolution technology at baseline and 2, 4, 8, 12, and 16 weeks after STZ injection. Radial function was analysed using conventional M-mode, and velocity, strain and strain rate imaging. Longitudinal function was analysed using pulsed Doppler imaging of the mitral annulus.


RESULTS
In the diabetic rats, a significant increase in LV end diastolic and end systolic diameter was measured when compared with controls (P < 0.001). Fractional shortening and LV ejection fraction remained unchanged in both groups. Using DMI, diabetic rats demonstrated a decrease in radial systolic velocity (rate of change: +0.01 vs. -0.003 week(-1); P < 0.01) and radial systolic strain rate (+0.003 vs. -0.205 week(-1); P = 0.08) of the anteroseptal wall. Histologic examination revealed dilated cardiomyopathy with no signs of fibrosis.


CONCLUSIONS
Although LV ejection fraction remained preserved, velocity and strain rate imaging was able to detect radial systolic dysfunction in diabetic rats. The absence of histological signs of fibrosis suggests that other mechanisms play a role in the development of diabetic cardiomyopathy.
Weytjens
Caroline
C
Department of Cardiology, In Vivo Cellular and Molecular Imaging Center, University Hospital, Brussels, Belgium. igwsc@uzbrussel.be <igwsc@uzbrussel.be>
Franken
Philippe R
PR
D'hooge
Jan
J
Droogmans
Steven
S
Cosyns
Bernard
B
Lahoutte
T
T
Van Camp
Guy
G
D000818:Animals; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000209:etiology; D048909:Diabetes Complications / Q000150:complications*; D004195:Disease Models, Animal; D015150:Echocardiography, Doppler; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology