Evaluation Of Left Ventricular Function In Patients With Complete Left Bundle Branch Block By Real-Time Three-Dimensional Speckle Tracking And Conventional Echocardiography

Objective: The left ventricular function changes of complete left bundle branch block(CLBBB)were evaluated by using real-time three-dimensional speckle tracking(3D-STI)and conventional echocardiography Methods: Selected 35 cases with isolated complete left bundle branch block(CLBBB)of which the coronary artery stenosis is less than 50 % conformed by coronary angiography,to be divided into two groups based on left ventricular ejection fraction(LVEF): LVEF ≥50% in 18 cases(group A)including 11 male patients,and 7 female patients,aged 32-61 years,with an average age of 54.5 years;EF<50% in 17 cases(group B)including 10 male patients and 7 female patients,aged 52-79 years,with an average age of 60.1 years.The other group is the healthy control of 30 patients(group C),including 15 males and 15 females,aged 30-75 years,with an average age of 53.6years.There was no statistical significance on differences in height,weight and blood pressure between groups.Group A and B were diagnosed as CLBBB based on the electrocardiogram manifestation,excluding factors such as hypertension,myocardial infarction,myocardiopathy,valvular heart disease,pericardial effusion,other cardiac arrhythmias and pulmonary arterial hypertension and so on.The conventional two-dimensional echocardiogram and three-dimensional speckle tracking imaging technology were used to determine the left ventricular structure and function-related parameters in three groups.1,The conventional ultrasonic parameters were measured: left atrial diameter(LAd),left ventricular end-diastolic diameter(LVDd),interventricular septal depth(IVSTd),and left ventricular posterior wall thickness(LVPWd),left ventricular end systolic diameter(LVSd).The left ventricular ejection fraction(LVEF)was measured by using the Simpson methods.,and the mitral orifice peak velocity E in early diastolic phase and peak velocity A in late diastolic phase were measured by spectral Doppler,with calculation of E / A ratio;The speed of mitral annulus on left ventricular side in early diastolic phase(E’)was measured by Tissue Doppler imaging with calculation of E/ E’ ratio.2,The three-dimensional strain parameters: left ventricular global longitudinal peak systolic strain(LVGLS),left ventricular global circumferential peak systolic strain(LVGCS),left ventricular global radial peak systolic strain(LVGRS),left ventricular global area peak systolic strain(LVGAS),and three-dimensional strains of the basal,medial,and apical portions of the left ventricle between the groups.Results:Conventional echocardiographic parameters: Compared with control group C and A,LVEF in group B was lower,with statistical significance(P < 0.05);LAd,LVSd and LVDd in group B increased compared with control group C and A,with statistical significance(P < 0.05);E/A decreased in group A and B compared with control group C,with statistical significance(P < 0.05);E/E’ in group B increased compared with control group C and A,of which the difference was statistically significant(P < 0.05).Three-dimensional strain parameters: LVGLS,LVGRS,LVGCS and LVGAS in group A and group B were lower than those in group C(P < 0.05),with statistical significance.Compared with group A,LVGLS,LVGRS,LVGCS and LVGAS in group B were lower(P < 0.05),with statistical significance.The three-dimensional myocardial strain values in the basal,middle and apical segments of the left ventricle decreased gradually(p<0.05),of which the difference was statistically significant.LVGLS,LVGRS,LVGCS and LVGAS in anterior wall and anterior septum of left ventricle were significantly lower than those in lateral wall,inferior wall,inferior wall and posterior septum(p < 0.05),of which the difference was statistically significant.Conclusion:The left ventricular myocardial motion was not coordinated in CLBBB patients,mainly including antetheca and front interval changes,which resulted in the global and regional myocardial dysfunction of left ventricular.Three-dimensional speckle tracking can be used to evaluate the left ventricular systolic function in CLBBB patients early,sensitively and accurately,of which the LVGLS is more sensitive to evaluate the left ventricular dysfunction in CLBBB patients.