Assesment Of Left Ventricular Systolic Synchrony In Dilated Cardiomyopathy Patients With Normal Or Wide QRS Duration By Velocity Vector Imaging

Objective: To assess the contraction synchrony of the left ventricle (LV) in dilated cardiomyopathy(DCM) patients with normal or wide QRS duration by velocity vector imaging (VVI).To evaluate the relation of LV contraction synchrony with QRS duration,LV function and LV remodeling in DCM patients.Materials and Methods:Sixty normal subjects who were matched with study group in age and gender (34 men ,26 women; average 55.38±9.92 years) and sixty seven DCM patients (39 men,28 women; average 58.28±10.59 years) were included. Based on QRS duration, study group divided into normal QRS group(QRS duration<120 ms) and wide QRS group(QRS duration≥120 ms).31 patients(average 57.25±10.25 years) were included in normal QRS group, 36 patients(average 59.14±10.94 years) were included in wide QRS group. QRS duration were measured with Standard 12-lead electrocardiograms and left ventricular ejection fraction (LVEF),left ventricular end-diastolic volume(LVEDV),left ventricular end-systolic volume (LVESV),LV end-diastolic diameter (LVEDD),left ventricular end-systolic diameter(LVESD),left ventricular fractional shortening (LVFS) were measured with conventional echocardiography. VVI was done in all three standard LV apical views and parasternal LV short axis(SAX) views.According to 16 segments analysis method, the time to peak systolic longitudinal velocity (Tvl) was derived from the LV apical views ,the time to peak systolic radial velocity (Tvr) and to peak systolic circumferentialstrain (Tsc) were derived from the LV short axis views. The standard deviation of Tvl, Tvr and Tsc (Tvl-SD,Tvr-SD and Tsc-SD) of 16 LV segments and the maximal temporal difference of Tvl ,Tvr and Tsc (Tvl-dif ,Tvr-dif and Tsc-dif) between any 2 of the 16 segments were calculated.Results: 1. LVEDD, LVESD,LVEDV and LVESV were significantly larger in the normal QRS group and wide QRS group than in the normal control group( P≤0.01). LVEF and LVFS were more lower in the normal QRS group and the wide QRS group than in the normal control group(P≤0.01).There were no difference of LVEDD,LVESD,LVEDV,LVESV,LVFS and LVEF in the normal QRS group and the wide QRS group(P≥0.05).2. There were no significant difference of Tvl,Tvr and Tsc in LV 16 segments in normal subjects.3. Tvl-SD,Tvr-SD,Tsc-SD,Tvl-dif,Tvr-dif and Tsc-dif were significantly higher in the normal QRS group and wide QRS group than normal control group ( P≤0.01), but there were no difference in the normal QRS group and the wide QRS group(P≥0.05).Tvl-SD=36.00ms,Tvr-SD=35.82ms,Tsc-SD=38.09ms were consider- ed as cut-off values for dyssynchrony indexes of longitudinal,radial and circumferential strain contraction of LV, there were 12/31(38.71%),13/31(41.94%), 13/31(41.94%)intraventricular dyssynchrony in normal QRS group and 22/36(61.11%),23/36(63.89%),22/36(61.11%)intraventricular dyssynchrony in wide QRS group.Tvl-dif=101.90ms,Tvr-dif= 104.95ms,Tsc-dif=102.90ms were considered as cut-off values for dyssynchrony indexes of longitudinal,radial,circumferential strain contraction of LV,there were 13/31 ( 41.94% ) , 12/31(38.71%) ,13/31(41.94%)intraventricular dyssynchrony in nomal QRS group and 22/36(61.11%),23/36(63.89%),22/36(61.11%) intraventricular dyssynchrony in wide QRS group.There were no significant difference of LV dyssynchrony in the nomal QRS group and in the wide group(P≥0.05).4.The parameters of contraction asynchrony of LV in DCM patients were negative correlation with LVEF and positive correlation with LVEDD,LVESD,LVESV,but there were no correlation with QRS duration.Conclusions:1. In normal subjects, systolic movement of LV was highly consistent.2. By VVI assessment,The majorty of DCM patients with wide QRS duration have intraventricular dyssynchrony,but some of DCM patients with normal QRS duration also have intraventricular dyssynchrony. Linear correlation analysis showed that contraction asynchrony of LV was no significant correlation with the QRS duration.3.Contraction dyssynchrony of the LV could decline LV systolic function in DCM patients.4.VVI assessed LV contraction synchrony movement objectively,accurately and noninvasive,it has important applicative value before and after CRT.