| Objective:To analyze left ventricular systolic asynchronicity in patientswith complete right bundle branch block (CRBBB) using ultrasonic velocityvector imaging (VVI), to provide practical and reliable patho-physiologicalbasis for precise clinical evaluation of CRBBB.Materials and methods:1. Research subjectives:Thirty one patients with CRBBB in test group (22 men, 9 women;average age 56.87±13.6 years); twenty six normal subjects in normal controlgroup (18 men, 8 women; average age 52.55±12.65 years). The leftventricular ejection fraction (LVEF) and left ventricular end-diastolicdiameter (LVEDD) were measured and calculated using M-modeechocardiograpic techniques.2. Image collection:Siemens Acuson Antares echocardiography system was utilized for thedynamic gray-scale images collection of the left ventricle in 3 completecardiac cycles which were acquired in three short-axis views and three long-axis views (including standard mitral annulus view, papillary muscleview, apical left ventricle short-axis view, four-chamber view, two-chamberview and left ventricle long-axis apical view). All the two-dimensionaldynamic images were stored digitally and analyzed off-line with dedicatedvelocity vector imaging software and workstation. According to 18 segmentsanalysis method, the time to peak systolic longitudinal strain (Tsl) wasderived from the LV apical views , the time to peak systolic radial strain (Tsr)and to peak systolic circumferential strain (Tsc) and to peak of rotation angle(Tra) were derived from the LV short axis views. The standard deviation ofTsl, Tsr, Tsc and Tra (Tsl-SD, Tsr-SD, Tsc-SD and Tra-SD) of 18 LVsegments were calculated.Results:1. There was no statistically significant difference of age, weight, bloodpressure, LVEDD and LVEF between CRBBB group and the normal controlgroup. (table 1, P > 0.05)2. All of the left ventricular systolic dissynchronized index(Tsl-SD,Tsr-SD, Tsc-SD, Tra-SD) values of 18 segments in the control group was lessthan the definition of the dissynchronized index cut off values 32.6ms[6].(table 2)3. Left ventricular dyssynchrony index (Tsl-SD, Tsr-SD, Tsc-SD, Tra-SD) between CRBBB group and normal control group were 27.65±6.78vs 26.55±6.99, t=0.592, p=0.556; 32.63±11.82 vs 26.63±6.70, t=2.255,p=0.28; 42.81±9.72 vs 30.53±8.71, t=4.911, p=0.00; 37.01±7.73 vs27.67±7.11, t=4.98, p=0.00, respectively. Compared with the dyssynchronyindex of normal control group, left ventricular asynchronization index inCRBBB group increased, but only Tsc-SD and Tra-SD with significantdifference (P<0.05), Tsl-SD and Tsr-SD without significant difference (P>0.05). (table 2; chart 5)4. The contraction sequence of Tsc and Tra in normal control group wasfrom the previous interval to the inferior wall along with clockwise direction;the contraction sequence of Tsc and Tra in CRBBB group initialed at theposterior septium along with clockwise and counterclockwise to theventricular lateral wall at last. (table 3、4; chart 6)Conclusions:1. Systolic synchrony in each segment of left ventricular wall is good innormal control group.2. Compared to dyssynchrony index of normal control group, thepatients with CRBBB by VVI is out of synchronizaion at end-systole of LV,and the dyssynchrony performance in the rotation and circumferentialmovements is demonstrated obviously (P <0.05). 3. The sequences of time to peak circumferential strain and peak ofrotation angle of each segment in left ventricular between CRBBB group andnormal control group are inconsistent. |
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