Velocity Vector Imaging Quantification Of Left Ventricular Systolic Synchronicity In DCM Patients With Heart Failure

Objective:To assess the contraction synchrony of the left ventricle (LV) in normal subjects and in dilated cardiomyopathy(DCM) patients with serious congestive heart failure by velocity vector imaging (VVI) and compare the difference between them. To evaluate the relation of LV ontraction synchrony with and remodeling in DCM patients with serious congestiveheart failure. To evaluate the change of the segmental function of LV in DCM patients by VVI.Materials and Methods:Thirty normal subjects(18 men, 12 women; average age 47.62±16.99 years) and twenty five DCM patients with serious congestiveheart failure(19 men,6 women;average age 53.34±18.09years), 6 complete left bundle branch block were included, QRS duration≥120ms. DCM patients included in the study were selected on the basis of the following criteria: New York heart association (NYHA) class III~IV; Leftventricular end-diastolic diameter (LVEDD)≥60mm; Left ventricular ejection fraction (LVEF)≤35%.Standard echocardiography with VVI studies was performed on a Siemens Acuson Sequoia 512 echocardiography scanner with a 2.25–4.25 MHz cardiac transducer. Linking the electrocardiogram, all the subjects underwent conventional echocardiography examination and LVEF, LV end- diastolic volume(LVEDV), LV end-systolic volume(LVESV), LV end-diastolic diameter(LVEDd), LV fractional shortening (LVFS) were measured. The frame rate was kept between 70 and 100 Hz.Starting the VVI pattern, Two dimensional dynamic images of three standard apical views and three short views of two groups were collected with two or three consecutive cardiac cycle loops on digital cine loops at the end-expiration. All 2-dimensional dynamic images were stored digitally and analyzed off-line with syngo Velocity Vector Imaging software.A series of LV elocities, strain,and strain rate maps were observed in the standard LV apical views and the parasternal short axis views. According to 16 segments analysis method, the peak systolic longitudinal velocity(Vl), strain(Sl), strain rate(SRl)of each segment, the time to peak systolic longitudinal velocity (Tvl) and to peak systolic longitudinal strain(Tsl) was derived from the LV apical views , the peak systolic radial velocity(Vr), the time to peak systolic radial velocity (Tvr) and to peak systolic circumferential strain (Tsc) were derived from the LV short axis views. The longitudinal segmental ejection fraction of LV 16 segments were also obersed. The standard deviation of Tvl, Tvr and Tsc (Tvl-SD, Tsl-SD, Tvr-SD and Tsc-SD) of 12 LV segments and the maximal difference of Tvl ,Tvr and Tsc ( Tvl-dif ,Tvr-dif and Tsc-dif) between any 2 of the 12 LV segments in ejection phase were used as dyssynchrony index of longitudinal, radial, circumferential contraction dyssynchrony of LV.Results:1. Compared the control and the patients, there was no significant difference in age, sexuality and heart rate. DCM group had significantly larger LVEDD, LVESD and LVEDV than the normal control group (P<0.05 or P<0.01). The LVEF and LVFS were lower in DCM than in the normal control group (P<0.05 or P<0.01).2.①The value of Tvl and Tvr the 16 segments of LV had no significant difference in normal subjects (P>0.05).②The value of Tvl within the different wall of LV had significant difference in the DCM group (P<0.01).Compared with the values in the control group , the values of Tvl at basal and middle levels of the same wall and the values of Tvr in different segments of posterior, inferior and posteroseptal wall were significantly higher in the DCM group than those in the control group (P<0.05 or 0.01). The values of Tvl at apical levels of the posteroseptal, posterior and inferior wall had significant difference between two group(P<0. 05 or 0. 01). The value of Tsc was also significantly higher within the different segments of LV in the DCM group(P<0.05 or P<0.01).3.①T vl-SD and Tvr-SD of 12 segments were significantly higher in the DCM group compared with normal control group (all P<0.01). When a Tvl-SD of >33.10ms and >44.33ms(+1.65 SD of normal controls) were used to define significant systolic asynchrony, it was found in only 5/30(16.7%) and 2/30(6.7%) control subjects but was present in 21/25(84.0%) patients and 20/25(80.0%) in DCM group(all P<0.01), respectively. When a Tvr-SD of >35.80ms and >46.31ms(+1.65 SD of normal controls) were used to define significant systolic asynchrony, it was found in only 5/30(16.7%) and 4/30(13.3%) control subjects but was present in 21/25(84.0%) and 20/25(80.0%) patients in DCM group(all P<0.01), respectively. ②Tvl-dif and Tvr-dif of 12 segments were significantly higher in the DCM group compared with normal control group (all P<0.01). When a Tvl-dif of >101.5ms(+1.65 SD of normal controls) were used to define significant systolic asynchrony, it was found in only 3/30(10.0%) control subjects but was present in 21/25(84.0%) patients in DCM group(all P<0.01), respectively. When a Tvr-dif of >96.00ms(+1.65 SD of normal controls) were used to define significant systolic asynchrony, it was found in only 4/30(13.3%) control subjects but was present in 21/25(84.0%) patients in DCM group(all P<0.01), respectively.③Tsl-SD, Tsc-SD and Tsc-dif were significantly higher in the DCM group compared with normal control group (all P<0.01).④The locations of delayed contraction of 25 DCM patients are in the basal, middle segments of inferior(n=11), lateral(n=7), posterior(n=4) and posteroseptal wall(n=3). 4. In DCM group There was a significant negative correlation between Tvl-dif, Tvl-SD and LVEF(r=-807, P<0.01; r=-0776, P<0.01).There was a positive correlation between Tvl-dif, Tvl-SD and LVEDd, LVESV, LVEDV, correlation coefficient were 0.532, 0.457, 0.561 and 0.552, 0.413, 0.472(P<0.05)respectively. Tvr-dif and Tvr-SD were not correlated with LVEF, LVEDd, LVESV and LVEDV.5. There are good positive relationships between peak systolic longitudinal strain(S) and strain rate(SR)(P<0.05). In DCM group the value of S was correlated with longitudinal segmental EF in the basal anterior and the middle level of left ventricular wall(P<0.05). The value of SR was correlated with longitudinal segmental EF only in the basal anterior and midanteroseptal, midposterior, midanterior segments. The value of S and SR were not correlated with longitudinal segmental EF of left ventricular wall at apical level except for anterior.6. Postsystolic shortening (PSS) was detected in about two-thirds patients in DCM group, almost in all segments of left ventricular wall in the direction of long and short axis, among which were in more segments at basal and middle levels. PSS was most commonly detected in the long axis direction of lateral(n=11) and short axis direction of posteroseptal (n=14).Conclusions:1. In normal persons, systolic movement was highly consistent within different segments of LV. The result illustrates that systole movement is highly synchronized in LV.2. Serious asynchrony exists within the different wall and the different segment of LV in patients with CHF.3. The parameters of asynchrony of myocardium movement have close relations with function of LV and remodeling of LV. The result illustrates that contraction dyssynchrony of the LV could effect function and remodeling of LV.4. Strain and strain rate play an important role in evaluating the change of left ventricular systolic function in DCM patients.5. VVI could describe the longitudina1,radial and circumferential myocardial fiber movement motion features.VVI provides a simple, intuitional and noninvasive approach to assess the systolic synchronicity of all the LV segments, choose proper object for CRT and evaluate clinical effectiveness and prognosis of CRT.