The Research On Left Ventricular Dyssynchrony And Torsion Of Complete Left Bundle Branch Block

Two-dimensional speckle tracking imaging (2D-STI) is a new ultrasound technique which is based on the two-dimensional gray scale image, and it can be used to quantify cardiac wall motion. It is based on the two-dimensional image, frame by frame tracking image on myocardial pixel signal, feeling its velocity and the displacement change, which can quantitatively calculate myocardial motion and deformation. Compared with traditional dopple tissue, it has many advantages.2D-STI is more objective, angle dependent, not affected by ultrasound principle and the surrounding tissue stretch impact. It can more accurately and sensitively reflect myocardial regional and global systolic function.The purpose of this study is to find out the changes in cardiac function and left ventricular synchronization of different types of complete left bundle branch block patients. Meanwhile, we will further explore left ventricular torsion and rotation changes of left bundle branch block.The research included two parts:1. Evaluation of the Effect of Complete Left Bundle Branch Block on Left Ventricular Function and Mechanical Dyssynchrony by Two-Dimensional Speckle Tracking ImagingObjective:To evaluate the global left ventricular (LV) systolic function and mechanical dyssynchrony by two-dimensional speckle tracking imaging (2D-STI) in healthy volunteers, isolated complete left bundle branch block (CLBBB) patients and CLBBB patients with heart failure(HF). At the same time, the relationship between LV systolic function and mechanic dyssynchrony was investigated.Methods:Total60patients involved16healthy volunteers,29patients with asymptomatic CLBBB and20CLBBB patients with HF. Simpson method was used to measure left ventricular ejection fraction (LVEF).2D-STI was performed to measure average global longitudinal strain (GLPS-Avg) and time to peak longitudinal strain of eighteen segments (Ts-SD-18).Results:LVEF and GLPS-Avg of CLBBB patients with HF were significantly different (P<0.000) compared with the healthy volunteers. These two parameters were also significantly different (P<0.05) between asymptomatic LBBB and HF+LBBB. To compared with isolated CLBBB and healthy volunteers, Ts-SD-18was significantly higher in CLBBB patients with HF. On the other hand, Ts-SD-18was also higher in isolated CLBBB compared with healthy volunteers.Conclusions:Isolated CLBBB patients had more depressed LV systolic function than healthy volunteers had, even though their LVEF were in the normal range. And CLBBB patients with HF had severe LV systolic function. Compared with healthy volunteers, isolated CLBBB patients had an intermediate mechanical dyssynchrony, and CLBBB patients with HF had the most severe mechanical dyssynchrony.2. The effect of complete left bundle branch block on left ventricular radial dyssynchrony and rotation and twistObjective:The aim of this study was to investigate left ventricular (LV) radial dyssynchrony and LV rotational change of isolated complete left bundle branch block (CLBBB) and CLBBB with heart failure (HF).Methods:Twenty-six isolated CLBBB patients, twenty-four CLBBB patients with HF and twenty healthy controls were studied. Two-dimensional speckle tracking imaging (2D-STI) was applied to short-axis views to calculate LV radial dyssynchrony and LV rotational and twist degree and time to peak rotational and twist degree.Results:LV dyssynchrony and LV rotation and twist degree were intermediately damaged in isolated CLBBB patients and was significantly damaged in CLBBB patients with HF, compared with healthy controls.Conclusions:For isolated CLBBB patients, even if left ventricular ejection fraction (LVEF) was in the normal range, another parameters of cardiac mechanic had changed and2D-STI could be used to evaluate these alterations.