| Objective:To automatically measure left ventricular(LV) volume and sistolic function in patients with Hypertrophic Cardiomyopathy(HCM) using two-dimensional speckle tracking echocardiography(2DSTE), and to compare the results by2DSTE with those by cardiac magnetic resonance imaging (CMR) in order to explore the accuracy and feasibility for evaluating LV volume and systolic function in HCM patients using2DSTE. Methods:76HCM patients confirmed by echocardiography and (or) CMR were selected, and46subjects were included in the normal control group. Two dimensional echocardiography(2DE),2DSTE and CMR were carried out to detect left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) in all subjects, left ventricular volume was measured and correlation analysis on the systolic function was also performed. Time for collecting and analyzing images by using the three methods was recorded,respectively. Interobserver repeatability was assessed by two-way mixed intraclass coefficients (ICCs) with absolute agreement and their95%CIs to compare the methods of2DSTE and2DE. Results:LVEDV, LVESV and LVEF determined by2DSTE in the normal control group correlated well with the results by CMR (the r values were0.925,0.893,0.950, respectively, P<0.001), LVEDV, LVESV and LVEF determined by2DE in the normal control group c also orrelated well with the results by CMR (the r values were0.794,0.806,0.892, respectively, P<0.001). The differences among the values of LVEDV, LVESV and LVEF by using the three techniques were not statistically significant (P>0.05). On the other side, in HCM patients, LVEDV and LVESV determined by using the three methods significantly decreased in comparison to those in the normal control group respectively (P<0.001), while the LVEF determined by using the three techniques were not significantly different between the two groups (P>0.05). In HCM patients, LVEDV, LVESV and LVEF determined by2DSTE and2DE both correlated significantly with the results by CMR (2DSTE vs. CMR,the r values were0.858,0.721and0.761respectively, P<0.001;2DE vs. CMR,the r values were0.506,0.519and0.503respectively, P<0.05). In the comparisons of LVEDV,LVESV and LVEF by using the three techniques in the HCM patients, LVEDV determined by2DSTE was not significantly different from the values by using CMR (P>0.05); while, LVESV determined by2DSTE was higher than the values by using CMR(P<0.05), compared with CMR,2DSTE was slightly underestimated LVEF. Bland-Altman analysis of LVEF using both methods showed a mean difference of8.2with95%limits of agreement at±14%. LVEDV and LVESV determined by using2DE were significantly lower than the values by CMR (P<0.001), The differences of LVEF in HCM patients by using both methods were not statistically significant (P>0.05). LVEDV determined by using2DE were significantly lower than the values by2DSTE (P<0.001). Bland-Altman analysis of LVEF using both methods showed a mean difference of9.5with95%limits of agreement at±14.5%. Statistically significant differences can be detected in the comparisons among the time for collecting and analyzing images by using the three methods (P<0.001),2DSTE required the shortest time, the biplane Simpson's method by using2DE ranked the second, and CMR required the longest time. Interobserver repeatability was assessed by two-way mixed intraclass coefficients (ICCs) with absolute agreement and their95%CIs to compare the methods of2DSTE and2DE. The ICCs determined by using2DSTE (the ICCs of LVEDV and LVEF were0.93and0.88, respectively) were higher than those by2DE (the ICCs of LVEDV and LVEF were0.67and0.65, respectively). Conclusion:Left ventricular volume is an important indicator for the evaluations of patients with HCM. It's suggested that2DSTE can be used as an easy and accurate method to determine the LV volume, which can provide effective information for the evaluation of LV volume and systolic function in HCM patients and be of great potential in the clinical application. Objective:The study of correlation between left ventricular (LV) torsion mechanism and myocardial fibrosis in patients with Hypertrophic Cardiomyopathy(HCM)by using speckle tracking echocardiography(STE) was relatively peculiar in my cuntry and abroad. Our study was to evaluate left ventricular (LV) rotation angle and torsion characteristics of hypertrophic cardiomyopathy(HCM) patients by usingSTE, and to investigate the clinical values for evaluating LV torsion mechanism in hypertrophic cardiomyopathy patients by using STE. Methods:76HCM patientsconfirmed by echocardiography and cardiac magnetic resonance(CMR) were selected, and46subjects were included in the normal control group.The two-dimensionalimages with high frame rates of both groups were obtained by echocardiography, the torsion angles and the LV rotation angles at different levels were obtained bySTE. Left atrial end-systolic diameter (LADs), left ventricular end-diastolic diameter (LVEDd) and interventricular septal thickness (IVST) were measured by routineultrasound examinations; and left ventricular ejection fraction (LVEF) was calculated with biplane Simpson's method. Meanwhile comparative analysis was carried out on the parameters between the HCM group and the normal control group. CMR was performed on the HCM patients with myocardial delayed enhancement scanning, accoding to which, the patients were divided into the fibrosis group and non-fibrosis group. Mitral valvular early diastolic inflow velocity(E peak) was obtained using color Doppler flow imaging (CDFI), Mitral annular early diastolic velocity(Em) was abtained using tissue Doppler imaging (TDI), and the ratio of E/Emwas calculated. Left atrial volume was measured and left atrial volume index (LAVi) was determined. Meantime comparative analysis was carried out on the data between the fibrosis group and non-fibrosis group.Correlation analysis was accomplished on the LV torsion angle of the fibrosis group with the reinforced segment number by CMR, and the receiver characteristic curve (ROC curve) was plotted toevaluate the sensitivity and the specificity of LV torsion angle in predicting myocardial fibrosis in hypertrophic cardiomyopathy patients. Results:In comparison to the normal control group, rotation angle at the apical level and mitral valve level,LV torsion angle and LADs in the HCM patients were significantly higher (P<0.001), while the left ventricular end-diastolic diameter inthe HCM patients was significantly lower (P<0.05), and the difference in LVEF between the two groups was not statistically significant (P>0.05). After CMR examination, myocardial fibrosis was detected in49patients in the HCM group, whichaccounted for64.5%of the total76patients. LV torsion angle, rotation angle at the apical level, IVST, E/Emand LAVi in the fibrosis group were significantly higher than those in non-fibrosis group (P<0.001); while the differences in the rotation angle at the mitral valve level, LADs, LVEDd, LVEF were not statistically significant between the two groups (P>0.05). Left ventricular torsion angle was significantly correlated with reinforced segment number (r=0.785, P<0.001). It's showed in the ROC curve that the area under the curve was0.69by using left ventricular torsion angle to detect myocardial fibrosis (P<0.001,95%confidence interval (0.525～0.859). According to the ROC curve, the cutoff point for predicting myocardial fibrosis by using LV torsion angle was18.22, the sensitivity for prediction was73%, and the specificitywas86.9%. Conclusion:Left ventricular rotation and torsion angle in HCM patients can be accurately measured by using STE, according to which, LV myocardial dysfunction can be sensitively detected when LVEF is normal. The present study also indicates that STE can predict effectively myocardial fibrosis in HCM patients by detecting the LV torsion angle, which provides reliable evidences for the evaluation of medication therapy drugs and the prognosis, and that left ventricular torsion angle can be used as novel quantitative index for evaluating theprognosis in HCM patients. |
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