Usefulness of mitral annulus velocity for the early detection of left ventricular dysfunction in a rat model of diabetic cardiomyopathy.
BACKGROUND
Diabetic cardiomyopathy (DMCMP) is characterized by myocardial dysfunction regardless of coronary artery disease in diabetic patients. The features of LV dysfunction in rat model of type 1 DM induced by streptozocin, are variable and controversial. Thus, we tested the usefulness of tissue Doppler imaging in the early detection of ventricular dysfunction in a rat model of DMCMP.


METHODS
Diabetes was induced by intra-peritoneal injection of streptozocin (70 mg/kg) in 8 weeks of Sprague-Dawley rat. Diagnosis of diabetes was defined as venous glucose level over 350 mg/dL 48 hrs after streptozocin injection. Echocardiography was done at baseline and 10 weeks after diabetes induction both in diabetes group (n=15) and normal control (n=10). After echocardiography at 10 weeks, invasive hemodynamic measurement using miniaturized conductance catheter was done in both groups.


RESULTS
Ten weeks after diabetes induction, heart and lung mass indexes of diabetes were larger than those of normal control (3.2+/-0.3 vs. 2.4+/-0.2 mg/g, p<0.001, 5.5+/-1.1 vs. 3.6+/-0.6 mg/g, p<0.001, respectively). In echocardiographic data, s' (2.4+/-0.4 vs. 3.1+/-0.5 cm/s, p<0.001), e' velocity of mitral annulus (2.9+/-0.6 vs. 3.8+/-1.1 cm/s, p<0.001), and E/e' ratio (27.1+/-5.6 vs. 19.7+/-2.6, p<0.001) were impaired in diabetes group. In hemodynamic measurement, there were no differences in ejection fraction, peak dP/dt between the diabetic group and normal control. However, load independent indexes of contractility, the slope of the end-systolic pressure volume relation (0.18+/-0.07 vs. 0.62+/-0.18 mmHg/microL, p<0.001) and preload recruitable stroke work (51.8+/-22.0 vs. 90.9+/-22.5 mmHg, p<0.001) were impaired in diabetic group compared to normal control.


CONCLUSIONS
In a rat model of diabetic cardiomyopathy, tissue Doppler imaging of mitral annulus can be a good modality for early detection of myocardial dysfunction.
Kim
Dae-Hee
DH
Cardiovascular Center, Seoul National University Hospital, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Kim
Yong-Jin
YJ
Kim
Hyung-Kwan
HK
Chang
Sung-A
SA
Kim
Min-Seok
MS
Sohn
Dae-Won
DW
Oh
Byung-Hee
BH
Park
Young-Bae
YB