三维斑点追踪技术评价肥厚型心肌病患者左心室心肌力学特点

目的应用三维斑点追踪技术（3D-STI）评价不同程度室壁肥厚对肥厚型心肌病（HCM）患者左心室整体及局部心肌力学的影响。 方法纳入2016年4月至2017年12月于华中科技大学同济医学院附属协和医院确诊为HCM患者30例，同时纳入此时间段在该院行常规体检的正常对照组30例。根据左心室16节段的室壁厚度将HCM组分为4个亚组（HCM 1组，室壁厚度<1.1 cm；HCM 2组，室壁厚度≥1.1 cm且<1.5 cm；HCM 3组，室壁厚度≥1.5 cm且<2.0 cm；HCM 4组，室壁厚度≥2.0 cm）。研究对象均行常规超声及三维超声心动图检查。获取左心室整体纵向应变（GLS）、圆周应变（GCS）及径向应变（GRS），各节段纵向应变（SLS）、圆周应变（SCS）及径向应变（SRS），左心室质量（LVM）与左心室射血分数（LVEF）。采用独立样本t检验比较HCM组与对照组各指标的差异；采用单因素方差分析比较HCM各亚组间应变参数；采用Pearson或Spearman相关分析分析LVEF和室壁肥厚程度与左心室整体应变间的相关性。 结果与对照组比较，HCM组标化后LVM增加（122.3±29.7）g/m² vs （77.3±11.3）g/m²]，GLS、GRS减低（-14.7±3.6）% vs （-24.7±2.7）%，（36.2±8.3）% vs （47.7±3.0）%]，差异具有统计学意义（t=-7.761、-12.229、7.161，P均<0.001）；2组间LVEF、GCS比较，差异无统计学意义（P>0.05）；HCM组LVEF与GLS、GCS及GRS均存在相关性（r=-0.41，-0.88，0.66，P均<0.05）。HCM组GLS与标化后LVM呈线性相关（r=0.42，P<0.05）；HCM组GCS与最大室壁厚度、室壁厚度≥1.5 cm的节段数呈线性相关（r=0.35、0.48，P均<0.05）；GRS与最大室壁厚度、室壁厚度≥1.5 cm的节段数呈负相关（r=-0.55、-0.52，P均<0.05）。 结论HCM患者左心室整体与各节段心肌收缩功能损伤随室壁肥厚加重而加重。环向应变在HCM患者维持左心室收缩功能正常中可能起着重要的作用。

Investigation of left ventricular myocardial mechanics in patients with hypertrophic cardiomyopathy by three-dimensional speckle tracking echocardiography

ObjectiveTo investigate the impact of wall thickness on global and segmental myocardial systolic function in patients with hypertrophic cardiomyopathy (HCM) by three-dimensional speckle tracking imaging (3D-STI). MethodsThirty patients with HCM diagnosed at Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology were included in this study from April 2016 to December 2017, and 30 cases of normal controls who underwent routine physical examination during the same period were also included. According to the wall thickness, the HCM group was further divided into four subgroups (HCM 1, <1.1 cm; HCM 2, ≥1.1 cm to <1.5 cm; HCM 3, ≥1.5 cm to <2.0 cm; HCM 4, ≥2.0 cm). All subjects underwent conventional and three-dimensional echocardiography. The following parameters were obtained: left ventricular (LV) global longitudinal strain (GLS), circumferential strain (GCS) and radial strain (GRS), segmental longitudinal strain (SLS), circumferential strain (SCS) and radial strain (SRS), LV mass (LVM), and LV ejection fraction (LVEF). Independent sample t-test was used to compare the differences of each parameter between the HCM group and control group; one-way ANOVA was used to compare the strain parameters among HCM subgroups; Pearson or Spearman correlation was used to analyze the correlation between LVEF, ventricular wall thickness, and LV global strain. ResultsCompared with the normal control group, indexed LVM increased, and GLS and GRS decreased in the HCM group (122.3±29.7) g/m² vs (77.3±11.3) g/m², (-14.7±3.6)% vs (-24.7±2.7)%, (36.2±8.3)% vs (47.7±3.0)%; t=-7.761, -12.229, and 7.161, P<0.001 for all], while LVEF and GCS showed no significant difference (P>0.05). In the HCM group, LVEF was correlated with GLS, GCS, and GRS (r=-0.41, -0.88, 0.66; P<0.05 for all). There was a correlation between GLS and indexed LVM (r=0.42, P<0.05). GCS was correlated with the maximum wall thickness and number of segments with wall thickness≥1.5 cm (r=0.35, 0.48; P<0.05 for both). GRS were negatively correlated with the maximum wall thickness and number of segments with wall thickness≥1.5 cm (r=-0.55, -0.52; P<0.05 for both). ConclusionLV global and regional myocardial systolic dysfunction in patients with HCM aggravates as the degree of hypertrophy increases. GCS may play an important role in the maintenance of normal LVEF in HCM.