Quantitative Evaluation Of Left Ventricular Myocardial Mechanics With Volume Overload

Objective To evaluate the effect of volumetric overload on myocardial contractility of left ventricle using Two-dimensional speckle tracking echocardiography(2D-STI) and to establish the correlativity between strain and left ventricle end-diastolic volume index(LVEDVI).Methods 32 pre-dialysis patients who underwent AVF formation and 30 normal volunteers were enrolled in this study. Left ventricular end-diastolic volume(LVEDV) and end-systolic volume(LVESV) were measured by biplane Simpson method using two-dimensional echocardiography, then calculated left ventricular ejection fraction(LVEF) and left ventricular mass(LVM). According to 18 segments analysis method, the systolic longitudinal strain(LS) in the LV apical views and the systolic radial strain(SR) and systolic circumferential strain(SC) in the LV SAX views were measured using 2D-STE. Uremic patients in AVF formation before and after a month repeat the inspection.Compared the left ventricular systolic function parameters differences between the groups. In addition, the change of these parameters pre- and post-operation was also analyzed.LVEDV index(LVEDVI) and LVM index(LVMI) were obtained by normalized LVEDV with surface body area(BSA). Aeeording to normal range of LVEDVI from control group and the Clinical Echocardiography standard about LVEDVI, we divided the patients to 2 groups:Normal overload volume group(LVEDVI: ≤70ml/m2), Increase overload volume group(LVEDVI: >70ml/m2). Results ①In control group, the LV LS and CS had a decreasing trend from the apical segment to the basal segment,the LV RS was least in apical segment. In the AVF groups, the LV LS、RS and CS were were not statistically significant differences in basal segment, middle segment and apical segment. ②Pre-operative AVF group compared with the control group, the left ventricular segmental and global LS, CS, RS lower than in the control group; capacity increases left ventricular segmental and global LS, CS, RS is higher than the capacity of the normal group. ③Each segment of strain the AVF post-operation were reduced than pre-operation. ④LV GLS and correlation of LVEDVI: Y =-0.006X2+0.956X-25.719(Y: GLS, X: LVEDVI, R2 =0.703, R2>0.7 Description fit better), namely: LVEDVI<80ml / m2, GLS with LVEDVI increases, LVEDVI> 80ml/m2, GLS with LVEDVI decreases.Conclusion ①Left ventricular strain parameters change periodically with LV volume overload. ②The parameter of LV LS was sensitive to the change of pre-load and was volume-load dependent.