The Meaning Of Quantitative Tissue Velocity Imaging Assessment Of The Interventricular And Intraventricular Dyssynchrongy And Correlation To The QRS Duration In Chronic Heart Failure Patients

Objective We studied the possible occurrence of left interventricular and intraventricular dyssynchrony in CHF patients and analyzed the relation between the interventricular and intraventricular dyssynchrony and the QRS duration by QTVI to offer the indexes how to assess the interventricular and intraventricular dyssynchrony in CHF patients in clinic practices.Methods It was assessed that 30 patients with chronic heart failure in testing group (sinus rhythm,left ventricular ejection fraction(LVEF)<50%, left ventricular end diastolic diameter(LVEDd)>55mm, New York Heart Association classШ～IV), patients with nonsinus rhythm, valvular heart disease or hypertrophic cardiomyopathy were excluded.Based on QRS duration,18 patients (QRS duration<120 ms)were included in normal QRS group,12 patients (QRS duration≥120 ms) were included in wide QRS group.Control group included 16 normal healthy subjects who were matched with testing group in age and gender. Standard 12-lead electrocardiograms were acquired and the measurements of QRS duration were performed.The echocardiographic datas (e.g.left ventricular end diastolic diameter(LVEDd),left ventricular end systolic diameter (LVESd),left ventricular end diastolic volume(LVEDV) and left ventricular end systolic volume,(LVESV))were acquired from vivid 7(GE company)with EchoPac 6.2 workstation and TVI quantitive image analyzing soft ware. the aortic pre-ejection time was measured from the beginning of QRS complex to the beginning of the aortic flow velocity curve(PET-A)recorded by pulsed-wave(PW)Doppler.The pulmonary pre-ejection time was measured from the beginning of QRS complex to the beginning of the pulmonary flow velocity curve (PET-P)recorded.The difference between the two values(PET-AP) was defined as the interventricular dyssynchrony; The duration from the beginning of ECG QRS wave to the beginning of S waves between left and right lateral wall basal segment (interventricular mechanical delay,IVMD)were measured by QTVI.An PET-AP or IVMD≥40ms was considered as the cut-off value for interventricular dyssynchrony.All subjects were underwent QTVI to evaluate left ventricular dyssynchrony.The left ventricle was divided into 6 walls ,each wall included basal and middle segment,so there were 12 segments in left ventricle.Furthermore,myocardial regional velocity curves of the 12 segments were constructed from the digitisted images,the duration from the beginning of ECG QRS wave to the beginning of S wave(Ts) were measured.The maximum differences(Ts-max) and standard deviations(Ts-SD) of Ts were calculated.An Ts-max≥100ms or Ts-SD≥32.6ms was considered as the cut-off value for intraventricular dyssynchrony.Rusult1.There was no difference in age and gender between the CHF patients and normal controls,and no difference among the normal QRS group and the wide QRS group(all P>0.05).The QRS duration of ECG was longer in the wide QRS group than that of the normal control group and the normal QRS group (P<0.01).It had significantly larger LVEDd, LVESd,LVEDV and LVESV in the normal QRS group and wide QRS group than the normal control group(all P<0.01).The LVEF was lower in the normal QRS group and in the wide QRS group than in the normal control group(all P<0.01).2.It had significantly larger PET-A,PET-AP and IVMD in the normal QRS group and wide QRS group than in the normal control group(all P<0.01), and PET-A,PET-AP and IVMD were larger in the wide QRS group than in the normal QRS group (P<0.01).But PET-P was no difference in those groups (P>0.05). PET-AP≥40 ms or IVMD≥40 ms was considered as a cut-off value for interventricular dyssynchrony,there was no interventricular dyssynchrony in the normal control group,but there was 5/18(27.78%) interventricular dyssynchrony in the normal QRS group and 9/12(75.0%)interventricular dyssynchrony in the wide QRS group,the cases with interventricular delay in the wide QRS group was more many than in the normal QRS group(Fisher's P=0.024),and linear correlation showed that IVDM or PET-AP which represented interventricular dyssynchrony was positive correlation with QRS duration(r=0.59,P<0.01;r=0.56,P<0.01).3.It had significantly larger Ts,Ts-max and Ts-SD in the normal QRS group and the wide QRS group than in the normal control group(all P<0.01),but they were no difference of Ts-max and Ts-SD in the normal QRS group and the wide QRS group(P > 0.05). Ts-max≥100ms or Ts-SD≥32.6ms was considered as a cut-off value for intraventricular dyssynchrony,there was no intraventricular dyssynchrony in the normal control group,but there was 10/18(55.56%),10/18(55.56%)intraventricular dyssynchrony in the normal QRS group and 10/12(83.33%),8/12(66.67%)intraventricular dyssynchrony in the wide QRS group, but it was no significant difference in the test groups(Fisher's test P=0.235 or P=0.709).It demonstrated that intraventricular dyssynchrony was not only exhibiting in patients with wide QRS complex but also exhibiting in patients with normal QRS complex. And linear correlation showed that Ts-max or Ts-SD which represented intraventricular dyssynchrony was not correlated with QRS duration(r=0.28,P>0.05 or r=0.29,P>0.05). Conclusion1.The normal control group had interventricular and intraventricular synchrony.2.By quantitative Tissue Velocity Imaging assessment,almost of CHF patients with wide QRS complex have interventricular and intraventricular dyssynchrony,but some of CHF patients with normal QRS complex also have interventricular and intraventricular dyssynchrony.3.QTVI may detect interventricular and intraventricular dyssynchrony of CHF patients.