| Objective: To observe the changes on myocardial motion in systolic phase withechocardiogram and tissue tracking imaging (TTI) in dilated cardiomyopathy(DCM) patients with serious congestive heart failure (CHF). To assess myocardialsystolic asynchrony of left ventricle (LV) in DCM patients with wide and normalQRS interval. To evaluate the clinical application value of TTI.Methods: 39 DCM patients included in the study were selected on the basis of thefollowing criteria: New York heart association (NYHA) class III~IV; Leftventricular end-diastolic diameter (LVEDD)≥60mm; Left ventricular ejectionfraction (LVEF)≤35%. According to QRS duration, the patients were divided intotwo groups: Normal QRS interval subjects(DCM I) 20, average age(51.0±8.0);Prolonged QRS interval subjects(DCM II) 19, average age(53.2±8.9); Normalcontrol subjects(Normal control group) 23, average age(44.8±16.5). Standardechocardiography with Doppler studies was performed on a Vivid VIIechocardiography scanner with a 1.7/3.4MHz transducer. Standard echocardio-graphy, Color Doppler flow imaging and TTI were performed with the patient inthe left lateral decubitus position. The following echocardiographic parameterswere measured: (1) LVEDD; (2) LV end-systolic diameter (LVESD); (3) LVEF;and (4) LV fractional shortening (LVFS). Aortic and pulmonary Doppler flowswere recorded in the pulsed mode from the apical five-chamber view andparasternal short-axis view, respectively. TTI (frame rates>70 fps-1) was performedin the apical views (four chamber, two chamber, and long axis) for the long axismotion of the LV. TTI cine loops containing five consecutive cardiac cycles werestored digitally for post-processing. The following ventricular walls wereinterrogated: septal, lateral, anterior, inferior, anteroseptal and posterior wall andtheir color tissue displacement image were observed. In each view, Mitral annulus,basal and mid segments were assessed. For the measurement of timing, thebeginning of the QRS complex was used as the reference point, where the time topeak myocardial systolic displacement(Ds) was measured by TTI and was rectifiedby dividing√R-R interval into it(Ts). For the assessment of synchronism, therange (Ts-R), standard deviation (Ts-SD) and coefficient of variation of Ts (Ts-CV)in all 12 myocardial segments were calculated. The time from the onset of the QRScomplex to the onset of the aortic and pulmonary waves was measured and wasrectified by dividing√R-R interval(Ta, Tp). The difference between the aortic andpulmonary ejection delays (Ta-p) was used to assess inter-V systolic asynchrony.To assess LV myocardial motion and systolic function, the Ds from mitral annulus,basal and mid segments were measured. All measurements were performed 3 timesand results averaged.Results:1. DCM I and DCM II had significantly larger LVEDD and LVESD than thenormal control group (all P<0.001). The LVEF and LVFS were lower in DCM Iand DCM II than in the normal control group (all P<0.001). Between DCM I andDCM II were no significant difference (P>0.05).2. In normal subjects, Color tissue displacement image displayed that thedisplacement of LV walls was gradually descendent from cardiac base to apex andthe displacement in mitral annulus was maximal. In a same section, the wallsalmost simultaneous started to move from cardiac base to apex. In some DCMpatients, systolic dyschronization of LV walls could be observed. TTI showed thata certain wall still remained gray and coloring delayed when corresponding wallstarted to coloring.3. In normal control group, TTI displayed that the curve of displacement waspositive upward wave and the Ds of LV walls was gradually descendent fromcardiac base to apex. At a same section, Ds of PW exceeded that of AS (P<0.001),Ds of IW exceeded that of AW (P<0.01). At base of six LV walls, Ds of IW, PW,LW and PS was maximal and that of AS was minimal (P<0.001). To compare withnormal subjects, shape of displacement curves of DCM patients was abnormal andamplitude of wave was low. Ds of mitral annulus, basal and middle segment waslower in DCM I and DCM II than in the normal control group (all P<0.001).Between DCM I and DCM II are no significant difference (P>0.05).4. There are good positive relationships between mean Ds in mitral annulus andLVEF in DCM group and normal control group (r1=0.80, P<0.001; r2=0.85,P<0.001).5. The Ts-R, Ts-SD and Ts-CV were significantly prolonged in DCM I and DCM IIcompared with normal control group (all P <0.01). When a Ts-R of > 108.29 ms, aTs-SD of >35.63ms and a Ts-CV of >0.09(+1.65 SD of normal controls) were usedto define significant systolic asynchrony, it was found in only 3/23(13.0%) controlsubjects but was present in 11/20(55.0%) patients in DCM I (P <0.01) and 14/19(73.7%) in DCM II (P <0.001), respectively. Ts-R, Ts-SD and Ts-CV were alsolarger in DCM II than in DCM I (all P <0.01). The locations of delayed contractionof 39 DCM patients are in the basal posteroseptal (n=11), midposteroseptal (n=10),midinferior (n=10), basal anteroseptal (n=3), basal posteroseptal accompanyingbasal inferior (n=2), midlateral (n=2), basal lateral (n=2), midanteroseptalsegments (n=1).6. There are poor positive relationships between Ts-R, Ts-SD, Ts-CV and QRSinterval (r1=0.53, r2=0.51, r3=0.51; all P<0.01) in DCM group.7. In DCM group, there are fairly poor relationships between LVEF and Ts-R,Ts-SD, Ts-CV (r1 =-0.34, r2 =-0.33, r3 =-0.35; all P<0.05).8. The Ta and Ta-p were significantly prolonged in DCM I and DCM II comparedwith normal control group (all P<0.05). When a Ta-p of > -30.60ms and <24.24ms(±1.96 SD of normal controls) were used to define significant inter-V systolicasynchrony, it was found in only 1/23(4.3%) control subjects but was present in8/20(40.0%) patients in the DCM I (P<0.01) and 11/19 (57.9%) in the DCM II(P<0.001), respectively. The cases of inter-V systolic asynchrony were 14/19(73.7%) in DCM patients with LV systolic asynchrony, and they were only5/14(35.7%) in DCM patients without LV systolic asynchrony. They existedsignificant difference (P <0.05).Conclusions:1. The displacement of LV walls and LV systolic function in DCM patients isobviously depressed, and TTI can be used to assess motion of regional LV wallsand LV systolic function by measuring systolic longitudinal displacement inregional LV myocardium and mitral annulus.2. The prevalence of LV systolic asynchrony was extensive in DCM patients ofserious CHF with a normal QRS duration and wide QRS complexes. The QRSinterval could not represent LV systolic synchronization.3. The types of asynchrony in all DCM patients are different. Their locations ofdelayed contraction were more frequent on the PS, PW and IW. The QRS intervaland shape could not distinguish the types of asynchrony. The evaluation ofsynchronism before pacing conduces to discovering promptly myocardial motionabnormality, confirming the type of asynchrony so as to select optimal opportunityof CRT and pacing position for improving therapeutic efficacy.4. TTI may provide more information than conventional echocardiography inshowing the changes of myocardial systolic displacement and time. TTI can beused to quickly, conveniently demonstrate left ventricle systolic motion andsystolic asynchrony.5. Parameter of aortic and pulmonary Doppler flows cannot completely reflectinter-V systolic asynchrony. |
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