| Backgruond:With the ascending of the blood pressure as its main clinical manifestation, Essentialhypertension (EH) refers to a disease accounting for95%of patients with hypertension.As a frequently-occuring disease which can endanger human health,it results from thecombination of complex pathogenesis and has genetic tendency.High blood pressure hasbeen shown to be the most important risk factor of cardiovascular disease in China. As atarget organ, the heart is strongly related to hypertension，and its main detriment is thatthe extra load in the heart will lead to harmful myocardial remodeling, which is mianly"left ventricular remodeling",and this remodeling will inevitablely lead to changes incardiac function. Therefore, monitoring ventricular dysfunction caused by hypertensionis particularly important for the prevention and treatment.Speckle tracking imaging (speckle tracking imaging, STI) is a new technologyevolved upon the theory of strain and strain rate imaging. By tracking spots ontwo-dimensional ultrasound images the myocardial tissue velocity, strain, strain rate areobtained in order to analyze the myocardial motion.It isn’t based on Doppler principleand thus has no angular dependence, for this it has greater advantages than tissueDoppler imaging.Objective：This study was conducted to evaluate speckle tracking imaging (STI) in assessmentof left ventricular systolic function,by using STI to assay systolic peak longitudinalstrain(SLs) of both hypertensive patients and nomal contral group, so as to provideevidence for clinical evaluation of the cardiac function in hypertensive patients.Materials and Methods： Study population consisted of40normal subjects (control group),60hypertensivepatients(H group) and30hypertensive patients with heart failure(HHF group). Subjectsare examined using GE Vivid7Diasonograph, M4S probe, the probe frequency of1.7~3.4MHz, a frame rate of50to90frames/sec, V3-D heart probe, the probe frequencyof2.0~4.0MHz. Subjects sat10minutes to start checking, checked connection of ECG,took left lateral decubitus position and calm breathing. For each section image, stored inthe machine, and then made off-line analysis, the data was automaticly analyzed bybuilt-in software of the Diasonograph. Take the standard2-D gray-scale images,measureed left atrium dimension (LAD), left ventricular end-diastolic dimension(LVEDd), diastolic interventricularseptal thickness (IVSTd) and left ventricularend-diastolic wall thickness (LVIDd).Then M-mode Echocardiography was used tomeasure left ventricular ejection funcction (LVEF), Pulsed-wave Doppler of transmitralwere obtained form the apical four chamber view．The following parameters weremeasured：peak velocity of early rapid filling(E),peak Velocity of atrial filling(A) andthe ratio of E to A(E/A). Using real-time tree-plane echocardiography Simpson’smethod，the following parameters were measured：left ventricular end-diastolic volume(LVEDV), left ventricular end-systolic volume (LVESV),left ventricular ejectionfunction (LVEF), stroke volume (SV),cardiac output (CO),etc.. Using instrumentbuilt-in AFI, to start with the apical left ventricular long-axis view, selected theend-systolic three sides of the valve annulus and left ventricular endocardial apex, thesoftware automatically tracked the movement of myocardial region of interest, andimage was divided into basal segment of the wall, the middle segment and apicalsegments, a total of six segments, each wall segment of the analysis results were given,that a successful segment "√" and failed segment "×" automatic measurement of thelongitudinal myocardial systolic peak systolic strain ((SLs) and the average longitudinalsection peak systolic strain (GLS). In the same way left ventricular apical four-chamberview and apical two chamber view were analyzed. Finally the instrument provided18-bit three segments SLs of apical section, as well as the average strain (GLS-LAX,GLS-A4C, GLS-A2C) and left ventricular myocardial longitudinal systolic averagepeak strain (GLS-Avg)of each section. The software provided bull’s-eye plot of the subject automatically, and the data was recorded and analyzed statistically.Results:1. Conventional echocardiographyComparison of measurements among H gpoup, HHF group and the contral group:compared with the control group, left ventricular diameter increased significantly (P<0.05). Compared with the control group and no left ventricular hypertrophy （nLVH）group, the wall of left ventricular hypertrophy （LVH）group thickened, and LVMIincreased, the difference was statistically significant (P <0.05). LVEF of HHF groupwas significantly lower than that of both the contral group and H group (P <0.05).Compared with the control group, in both H group and HHF group E-wave reducted andE/A value decreased significantly (P <0.05)2. Real-time tri-plane echocardiography:Compared with the contral group and H group, EDV and ESV of HHF groupincreased while SV and LVEF reduced significantly.3. STI examination:3.1Left ventricular SLs of the contral group.The SLs curve of left ventricular cardiac cycle was a bimodal curve, accompanywith the myocardial contraction, strain valued from0to negative development, andreached the maximum negative value before and after the T-wave offset (end-systolic).In early diastole myocardium longated rapidly, strain valued from maximum negative to0, and began the positive development at the end-diastolic, then reached a maximumpositive value before and after the R wave peak in the next cardiac cycle,with themaximum SLs a negative value. Comparing different segments of the same wall, theabsolute value of SLs increased gradually from base to apex, rendered as a certain"polarity" that basal segment <middle section <apical segment3.2Comparison of SLs between H group and the contral groupCompared with the contral group, in the nLVH group the left ventricularmyocardium SLs absolute value of each segment were reduced, but only9.6%of thesesegments were significantly (P <0.05),24.2%ventricular segments of this grouppostsystoliely shortened(ie, peak time extened, SLs peak in the isovolumic relaxation period), compared with the control group the difference was statistically significant (P<0.05).Compared with the contral group and nLVH group, in the LVH group, SLs of16.7%segments of the left ventricular myocardial segments and each section of leftventricular as well as SLs peak of whole left ventricular, all reduced significantly (P<0.05).3.7%of the ventricular segments motioned discrepantly (ie, systolic curve SLswere positive, zero-strain curved above baseline), compared with control group, andnLVH group, the differences were statistically significant (P <0.05).3.3Comparison of SLs between HHF group and the contral group,H groupSLs of61.1%segments of the left ventricular myocardial reduced significantlycompared with the contral group and H group (P <0.05). SLs of each segment and eachsection of left ventricular as well as SLs absolute peak value of whole left ventricular,all reduced as the reduction of LVEF, which showed a good correlation with LVEF.53.7%ventricular segments of this group postsystoliely shortened ignificantlycompared with the contral group and H group (P <0.05).22.2%of the ventricularsegments motioned discrepantly,compared with control group, and nLVH group, thedifferences were statistically significant (P <0.05).Conclusion:1. speckle tracking imaging (speckle tracking imaging, STI) can accurately assessleft ventricular long axis motion in patients with hypertension, it is more accurate andmore sensitive compared with conventional echocardiography and real-time tree-planeechocardiography. Furthermore, STI can not only evaluate the whole left ventricularlong axis movement but also can evaluate the movement of each segment.2. STI is superior to conventonal echocardiography for no angular independence, ithas high repeatability and relatively simple process of analysis. STI matched the requestof U.S. Society of Echocardiography (ASE) for clinical use,and was transplanted inGEVV7. |
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