正常婴幼儿左心室心肌纵向应变及应变率的定量分析

Quantitative Analysis of Longitudinal Strain and Strain Rate of Left Ventricle in Normal Infants and Young Children

目的应用速度向量成像(VVI)技术定量分析正常婴幼儿左心室纵向应变及应变率的特点。资料与方法选取50例正常婴幼儿,分别测量心尖四腔、两腔及左心室长轴切面6个室壁3个不同水平节段(基底段、中间段、心尖段)的纵向应变峰值及应变率收缩、舒张期峰值。结果 41例婴幼儿(82%)左心室壁应变曲线呈平滑型,即曲线平滑无切迹;SR曲线呈双峰型,即收缩期S峰、舒张期呈单峰;前间隔、后间隔的应变、收缩期应变率、舒张期应变率由基底段至心尖段逐渐减小,但仅前间隔基底段应变与前间隔心尖段应变差异有统计学意义(t=1.79,P<0.05)。不同室壁同一水平节段及同一室壁不同水平节段的收缩期应变率比较,差异均无统计学意义(P>0.05)。结论多数正常婴幼儿舒张期左心室壁应变曲线呈平滑型,应变率曲线呈双峰型,可以为临床早期发现婴幼儿心肌运动异常提供借鉴。

Purpose To quantitatively evaluate longitudinal strain and strain rate （SR） of left ventricular （LV） in normal infants and young children using velocity vector imaging （VVI）. Materials and Methods A total of 50 normal infants and young children were enrolled in the study. The longitudinal strain peaks and SR peaks in three sections of LV walls during systole period and relaxation period were measured by VVI from apical tour-chamber view, apical two-chamber view and long axis view, respectively. Results Forty-one cases （82%） presented a smooth strain curve without incisures and a double peak in SR curve （systolic peak and single diastole peak）. The strain in anterior septum and posterior septum, the systolic SRs and diastolic SRs decreased from basal to apical segments. However, only the strain in basal segment and that in apical segment in anterior septum showed statistic difference （t=1.79, P〈0.05）; the systolic SRs of the same level in different walls and those in the same wall at different levels had no statistic difference （P〉0.05）. Conclusion Most normal infants and young children present a smooth diastolic strain curve and a double peak SR curve of LV, which can provide clinical guidance in the early diagnosis of myocardial abnormality for infants and young children.