Assessment of left ventricle function in early diabetic cardiomyopathy by Doppler tissue imaging

Xianyin WANG; Mingsong LIAO; Shusen LI; Pujie WANG; Jie TAO; Xiaoyan WEI; Linying MA

ABSTRACT

BACKGROUND:

Comparing with diabetic nephropathy and diabetic retinopathy, diabetic cardiomyopathy is put forward exceeded later and the research about it was not enough. It is difficult to detect diabetic cardiomyopathy in the earlier period so that it has usually been neglected.

OBJECTIVE:

To evaluate features of dysfunction of left ventricle in early diabetic cardiomyopathy by Doppler tissue imaging.

DESIGN:

Completely randomized and controlled experiment.

SETTING:

Ultrasound Department of General Hospital of Chengdu Military Area Command of Chinese PLA.MATERIALS The experiment was carried out at Ultrasound Department of General Hospital of Chengdu Military Area Command of Chinese PLA from March to June 2002. Totally 56 New Zealand rabbits of either gender were selected.

METHODS:

① Ten New Zealand rabbits was pulled out randomly from 56 as control group. The rest of 46 New Zealand rabbits were replicated diabetes mellitus by Streptozotocin (STZ), rabbits were absolute diet 18 hours and injected intravenously to ear marginal vein with 65 mg/kg of STZ. Then these rabbits were randomly divided into 4 groups as 2, 4, 6, 8th experimental group, with 10 rabbits in each group. ② Digit ultrasonic cardiogram equipment was used to examined interventricular motion of mitral annulus at 2nd,4th, 6th and 8th week in model groups and comparison group. The parameters such as systolic peak velocity (Sa), preejection period (PEP), local ejection time (ET), systolic mean velocity (Vm) of four various portions in mitral annulus and diastole early period velocity (Ea), diastole later period velocity (Aa), Ea/Aa were determined. ③ SPSS 11.0 was used for statistical analysis,one-factor analysis was adopted to compare difference of groups.MAIN OUTCOME

MEASURES:

The motion of lateral wall and posterior interventricular septum at mitral annulus were estimated by PW-DTI.

RESULTS:

Among 56 rabbits, 50 entered the final analysis and other 6 were lost because of failure modeling. Diastole dysfunction of left ventricle was discovered in STZ-inducod diabetic rabbits detected by tissue Doppler imaging at the 4th week. It showed that not only the tite of early period of diastole peak velocity (Ea) in mitral ring lateral wall and post-interval of left ventricle was reduced, but also the tite of Ea/Aa was reduced notably (P ＜ 0.05). Systolic dysfunction of left ventricle was discovered in STZ-in-duced diabetic rabbits detected by tissue Doppler imaging at the 6th week.It showed that local contraction peak velocity (Sa) of lateral wall and postseptum of mitral ring was decreased strikingly (P ＜ 0.05). Mean systole velocity of four various parts of mitral ring (Vm) was reduced at the 6th week (P ＜ 0.05). Pre-ejection period time (PEP) at post-septum and ejection time (ET) was elongated at lateral wall at the 8th week (P ＜ 0.05).

CONCLUSION:

① Diastolic dysfunction of left ventricle is characterized by decrease of early period of diastole peak velocity and the tite of Ea/Aa.② Systolic dysfunction of diabetic cardiomyopathy is characterized by decrease of local contraction peak velocity and elongation of pre-ejection period time and ejection time.