Assessment Of Left Ventricular Myocardial Asynchrony By Quantitative Tissue Velocity Imaging Technology In Patients With Dilated Cardiomyopathy

Objective: The purpose of this study was to assess the left ventricular myocardial asynchrony in patients with dilated cardiomyopathy by quantitative tissue velocity imaging technology, and to investigate the feasibility and accuracy of the technology for quantitative evaluation of the left ventricular mechanical asynchrony, and to analysis the correlation between asynchronous indexes and NT-proBNP.Method: 37 patients with dilated cardiomyopathy (DCM) and 30 healthy volunteers(contrast group,22 men,8 women; mean age 45.56±8.32 years ) were enrolled in this study. DCM patients were divided into two groups by QRS duration, 20 patients(16 men,4 women; mean age 48.45±13.31 years ) had a normal QRS duration (group DCMI) ,17 patients (14 men,3 women; mean age 48.24±12.91 years)had a prolonged QRS duration more than 120ms(group DCMII). All subjects were detected by using M-model,2-dimensional ultrasound and tissue doppler image. Measure parameters include left ventricular end-diastole, ejective fraction of left ventricle, shortening fraction and septum-to-posterior wall motion delay. Measuring the time from onset of QRS to peak velocity during systole (Ts ) at basal,middle and apical levels of the left ventricular walls by QTVI, and calculating the range and standard deviation of Ts,and the range of Ts of different segments in same level (Inter-Ts) and the range of Ts of different levels in same segment (Intra-Ts).Systolic peak velocity(Vs), early diastolic velocity(Ve) and late diastolic velocity(Va) were measured at mitral annulus. Plasma N-terminal pro-B-type natriuretic peptide were detected simultaneously in all subjects.Results : 1.Compared with the control group, LVEF,FS,Vs,Ve and Va decreased obviously in DCM groups(P<0.05),LVEDD and SPWMD increased in DCM groups (P<0.05); There were not significant difference between DCMI group and DCMII group.2. Inter-Ts of DCM I and DCM II groups were significantly longer than that of con group(P<0.01);Intra-Ts wes significantly different between con group and DCM groups in Inferior wall, lateral wall and posterior wall (P<0.05),but not within DCM groups(P>0.05).3.Ts, Ts-R and Ts-SD of DCM groups were significantly prolonged compared with con group(P<0.05) , Ts-R and Ts-SD of DCMII were raiser than that of DCMI group(P<0.05). Area under the ROC curve was 0.972 for Ts-SD that forecasted. Ts-SD>32.9ms was used as a cut-off point for prognostic test,the sensitivity was 88.50%,specificity was 93.10%.4.NT-proBNP was obviously increased in DCM groups, compared with the control group (P<0.01) ,there were not significant difference between DCM groups. NT-proBNP and Ts-R/Ts-SD was positive correlation(r=0.656,r=0.634,P <0.001), NT-proBNP and Vs was negative correlation(r=-0.727, P<0.001). Area under the ROC curve was 0.856 for NT-proBNP that forecasted. NT-proBNP >920Pg/ml was used as a cut-off point for prognostic test,the sensitivity was 83.80%, specificity was 84.40%.Conclusions: 1.In control group, the time to peak systole velocity was basely identical in different segments, health adult was completely synchronization.2.Asynchrony exist not only in different segments of same level, but also in different levels of same segment, means that asynchrony reside widely in patients with DCM.3.QTVI is considered as a technology on evaluating left ventricle function and asynchrony in patients with DCM. If QTVI is combined with NT-proBNP, they will provide more abundant and precise parameters for assessment the ventricle synchrony of DCM.