| Objectives:Recently,some clinical researches demonstrated that characteristics of diabetic cardiomyopathy were diastolic dysfunction in early stage and systolic dysfunction in late stage.It's debatable whether or not left ventricular systolic dysfunction exists in patients with subclinical diabetes mellitus(DM).Velocity vector imaging(VVI) is a novel technique which can non-invasively detect regional myocardial function.VVI is widely used to detect cardiac systolic function and can reflect subtle functional changes of regional myocardium.The purpose of this study is to assess subclinical left ventricular systolic dysfunction in patients with type 2 diabetes mellitus (2-DM) using VVI.Subjects and Methods:55 patients who visited Endocrine Research Institute in our hospital from May,2007 to November,2007.All the patients were diagnosed type 2 Diabetes mellitus(2-DM) and underwent observation and treatment.All patients were divided into two groups:patients with pure 2-DM 29 cases,patients with 2-DM and hypertension(2-DM&HP) 26 cases. Control group included 30 healthy subjects with normal X-ray and routine echocardiography test,without history of heart disease and organic diseases. The 30 healthy subjects were comparable with pure 2-DM patients in terms of sex and age.Patients with hypertension were excluded in pure 2-DM group, and exclusive criteria included:①presence of history of heart disease;②presence of thyroid disease;③presence of periphery vascular disease;④ presence of myocardial ischemic symptom;⑤abnormal electrocardiography;⑥EF＜55%when undergoing routine echocardiography;⑦other metabolic disease except 2-DM,connective tissue disease,dystrophy,severe dysfunction of liver and kidney,contact of toxic,alcohol abuse,pregnant woman in perinatal period.Two-dimensional images of apical four,two chambers and apical long-axis view were obtained with Sequoia 512 ultrasound system.The longitudial left ventricular regional systolic myocardial function was analyzed with VVI offline software.Parameters included myocardial velocity(Vmax), strain(Smax),strain rate(SRmax),and peak time of velocity(PTV),strain (PTS),strain rate(PTSR) in 16 segments of 6 ventricular walls.Each parameter was measured 2 times and average value was obtained.Results:Myocardial systolic Vmax gradually decreased from basal to apical segment with statistically significance in the control group(P＜0.01), whereas no differences were found about Smax and SRmax among basal, middle and apical segment(P＞0.05),The changes of Vmax,Smax and SRmax were identical in 2-DM and 2-DM&HP group.The longitudinal systolic myocardial Vmax,Smax,and SRmax in each segment were significantly lower in pure 2-DM and 2-DM&HP group than in the control group(P＜0.01),and with much lower in 2-DM&HP group compared with pure 2-DM group (P＜0.05).Longitudinal myocardial PTV,PTS and PTSR in each segment tended to prolong from control to2- DM and 2-DM&HP group,but there was no significantly difference(P＞0.05).Left myocardial PTV,PTS and PTSR were in good consistency in control group,without statistically differences among apical,middle and basal segment(P＞0.05).The changes of PTV,PTS and PTSR were identical in 2-DM and 2-DM&HP group.Conclusion:Systolic longitudinal parameters of left ventricule changed prior to presence of clinical symptoms in 2-DM patients,which indicated that 2-DM patients had subclinical left ventricular systolic dysfunction.All parameters in DM&HP group were lower than in 2-DM group,which indicated that 2-DM complicating hypertension could worsen myocardial impairment. VVI could objectively and sensitively detect subclinical left ventricular systolic dysfunction in patients with 2-DM and therefore could be a useful tool in assessing the myocardial regional systolic function.
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