目的 应用速度向量显像(VVI)技术评价肥厚型心肌病(HCM)患者左室心肌应变,识别其早期收缩功能异常.方法 随机入组40例HCM患者(HCM组)和25例全面体检健康者(对照组)行常规超声心动图检查,测量左室射血分数、左室内径及左室壁厚度.并采集胸骨旁二尖瓣水平、乳头肌水平、心尖水平短轴观和心尖四腔、三腔、二腔长轴观二维图像,脱机分析,得到纵向、环向应变的收缩期峰值及应变达峰时间.结果 ①除内膜环向应变外,HCM组各向应变显著小于对照组(P＜0.0001),应变的受损程度表现为纵向甚于环向.②HCM组仍基本保持对照组的应变特征性梯度,即内膜应变值显著大于外膜,外膜纵向应变自心底向心尖递减,内膜环向应变自心底向心尖递增.③HCM组各节段间应变存在显著不同步,同步性的损害纵向甚于环向,外膜甚于内膜.结论 VVI可以通过评价心肌纵向和环向应变,获悉左室心肌的局部和整体收缩功能,发现HCM患者的亚临床收缩力和收缩同步性异常.%Objective To analyze the strains of patients with hypertrophic cardiomyopathy (HCM) by vector velocity imaging(VVI),and to identify abnormal early systolic function.Methods Forty patients with HCM (HCM group) and 25 healthy subjects (control group) were enrolled.Standard two-dimensional echocardiography was performed.Left ventricular ejection fraction (LVEF),diameters and wall thickness were measured.Peak systolic strains in all directions and their time to peak were analyzed off-line.Results ①All but the endocardial circumferential strain were apparently smaller in HCM group than those in the control group(P ＜0.000 1).The difference was greater in long axis than that in short axis.②The HCM group maintained the characteristics of strain gradient as the control group,including the endocardiumepicardium gradient with endocardial strains was significantly greater than epicardial ones and the base-apex gradient,among which epicardial longitudinal strain decreased from the base to the apex and endocardial circumferential strain increased toward the apex.③The HCM group suffered significant dyssynchrony in terms of strain and rotation,with greater changes in longitudinal than in short axis,in epicardium than in endocardium.Conclusions VVI offers an overall assessment of regional and global left ventricular systolic function,including longitudinal and circumferential strain.Moreover,it can be used to evaluate subclinical systolic dysfunction and dyssynchrony in patients with HCM.
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