To Evaluate The Synchrony And The Function Of Ventricles In Bundle Branch Block Patients By Quantitative Tissue Velocity Imaging

ObjectiveThe complete left bundle branch block (CLBBB) and complete right bundle branch block (CRBBB) are common arrhythmia. It was reported that the incidence of CLBBB was 0.36‰and 0.09‰in the Age 40⁺ and in the Age 40^- respectively. The incidence of CRBBB was 2.9‰and 1.5‰in the Age 40⁺ and in the Age 40^-respectively. In this study, the synchrony and the systolic function of ventricles were assessed by quantitative tissue velocity imaging.MethodsSubjects with CLBBB (group II, n=17) , CRBBB (group I, n=20) , and healthy controls (n=20) were studied, and all the subjects were in sinus rhythm. A GE System-Five Ultrasound Machine was used to obtain echocardiographic images and analysis the function of quantitative tissue velocity imaging. Keeping the patients in left-lateral position, who breathe peacefully, then we recorded the ECG and measured the diameters of each compartment. The time from the beginning of the QRS to the beginning of pulsed wave of AV and PV of the patients and the control group. The time of inter ventricular mechanical delay (IVMD) was also calculated. Standard parasternal long-axis and apical four-chamber, two-chamber views were obtained. Observing the LW and PS and RV in apical four-chamber, the AW and IW in apical two-chamber, recording 3-5 cardiac cycles of TDI. Setting sampling volume in valve ring, we obtained the curve of speed-time, and measured the isovolumic contraction time(IVCT), isovolumic relaxation time(IVRT), filling time(FT), ejection time(ET), the systolic time, relaxtion time, the average peak velocities of S-wave and E'-wave and A'-wave.Results1. The left ventricular end-diastolic dimension and end-diastolic volume had no significant difference in statistics between group II and the control group. The left ventricular end-systolic volume and the left ventricular ejection fraction had significant difference in statistics between group II and the control group. All indexes were similar between the group I and control group.2. The IVMD and the Q-Ao had significant difference in statistics between group II and the control group. In group I, Q-PA and IVMD were significant longer in statistics than control group.3. In group II, the IVCT in the AW, LW, IW, PS were longer than that of the control groups. The IVRT in right ventricular free wall was lengthened. The FT and the diastolic period in left ventricular anterior, lateral and inferior were shorten. The ET and systolic period in left ventricular anterior, lateral, inferior, postero-septal and right ventricular free wall were shorten too. In group I, the IVCT in right ventricular free wall was lengthened than that of the control groups.4. The peak velocities (V_S,V_E) in left ventricular anterior, lateral and inferior wall were lower in group I than that of the control group. And they were similar in group I and control group.5. In group II, QRS and IVCT were taken on positive correlation. QRS and ET, QRS and Vs were taken on negative correlation.DiscussionTissue Doppler imaging (TDI) was developed on the base of tissue Doppler principle that can analyze and evaluate the low speed moved tissue. It could detect the vibration signal of wall motion with low frequency transduction and high amplitude. By now, many researches on ischemic heart disease, dilated cardiomyopathy, hypertrophic cardiomyopathy and hypertensive disease were performed by it to assess ventricular function.By comparing the peak velocity and the each duration, we found that Vs in every part of left ventricle were lower. V_E' was lower than V_A', IVCT was longer and IVRT in right ventricular free wall was longer in CLBBB group. In CRBBB group, only IVCT in right ventricular free wall was longer. It means that there were move delay and functional injury between left and right ventricular in CLBBB and CRBBB. In CLBBB, the move of left ventricular delayed significantly, and less delay was observed in right ventricular, indicating that it most likely influenced the function of left ventricular in CLBBB. And the move delay caused functional injury of right ventricular, but has no influence on move and function of left ventricular.In this study, we found an asynchronization of inner-left ventricular, and Q-AO was significantly longer than Q-PA. Therefore, we conclude that there is an asynchronization between left and right ventricular. We also found that constringency function was injured through lower ET compared with control in CLBBB. So we consider it is the basic reason that influences the function by constringency delayed and asynchronization of left ventricular.By analyzing the relationship between QRS duration and IVCT or ET in CLBBB, we found that the QRS duration takes on a significant positive correlation with IVCT and significant negative correlation with ET. So we think we can firstly judge the synchronism of wall motion by measuring the QRS duration. Since the Vs declined little by little and the QRS duration increased, we believe that we could firstly judge the constringency function of left ventricular by measuring the QRS duration. We conclude here that IVCT, ET and Vs may be the important parameter which can evaluate the constringency function and the degree of the inter-ventricular asynchronization in CLBBB.ConclusionQuantitative tissue velocity imaging can evaluate asynchronization and ventricular function of bundle branch block.