速度向量成像评价小儿扩张型心肌病左心室长轴收缩功能的研究

目的：探讨速度向量成像（VVI）技术评价小儿扩张型心肌病（DCM）患者左心室长轴收缩功能的准确性。方法：2H5例DCM患者和25例正常儿童为研究对象，应用VVI技术测量心尖四腔切面心肌运动速度、应变、应变率、达峰时间等指标。应用连续波多普勒记录的二尖瓣反流频谱检测左心室压力峰值变化率（LVdp／dtmax）。应用M型超声于左心室短轴切面测量左心室舒张末期内径、收缩末期内径，计算左心室射血分数（EF）。应用线性相关方法对各参数进行相关分析。结果：正常儿童左心室EF为65．8±4．2％，左心室各节段应变率波动于-1．26～-1．43／s；DCM患者左心室EF为41．2±14．5％，左心室各节段应变率波动于-0．31～-0．51／s；其绝对值明显低于正常儿童（P〈0．05）。DCM患者LVdp／＆max为521．8±283．4mmHg／s，DCM左心室侧壁基底段收缩期应变率与LVdp／dmaax高度相关（P〈0．05，r=0．86）。结论：DCM患者存在心肌收缩力减弱及收缩活动不协调，VVI技术可以比较准确地评价左心室长轴的收缩功能。

Study on longitudinal myocardial function of left ventricle in children with dilated cardiomyopathy using velocity vector imaging

Objective：To evaluate the accuracy of velocity vector imaging （VVI） in assessing the longitudinal myocardial function of left ventricle in children with dilated cardiomyopathy（DCM）. Methods：The peak systolic velocity（VS）, systolic peak strain（a）, systolic peak strain rate（SRS） and the time to peak systolic longitudinal velocity （TV） were measured in 25 children with DCM and 25 normal children in apical four chamber view using VVI. Left ventrieular dp/dtmax （LV dp/dtmax） were estimated using the spectrum of mitml regurgitant by continuous doppler. Left ventricular end-diastolic dimension （LVDD） and left ventricular end-systolic dimension （LVDS） were measured in short axis view of left ventricular with M mode ecliocardiography and ejection fraction （EF） was calculated. The correlation among different values was analyzed with linear regression. Results： The EF of the normal children was 65.8 ± 4.2 % and the SRS of all segments was - 1.26 - - 1.43/s;The EF of DCM children was 41.2 ± 14.5 % and the SItS of all segments was -0. 31 - -0. 51/ s;the absolute values of SRS in each segment in DCM group were lower than those of the normal children （ P 〈 0.05）. The LV dp/dtmax of DCM patients was 521.8 ± 283.4 mmHg/s, SItS of DCM correlated well with LV dp/dtmax （ P 〈 0.05, r = 0.86）. Conclusion： The longitudinal myocardial function of left ventricle in children with dilated cardiomyopathy could be accurately estimated by VVI.