肥厚型心肌病(HCM)是最常见与年龄相关的的心肌病，它的发病率在成年人中是0.02%到0.23%(即1/500)。在大约60%的患者是由常染色体显性遗传性基因疾病引起，主要特征是心脏肌小节蛋白变性，大约5%-10%的成年人HCM是由其他遗传性疾病(如：先天性代谢疾病、神经肌肉疾病、线粒体疾病等)引起。患者的典型特征为非异常负荷原因引起的左心室壁肥厚。其特征包括：心肌细胞排列紊乱，间质纤维化，异常冠状动脉微循环，心电图异常。 HCM的诊断是通过任何一种影像学方法检测左心室室壁的增厚(在一个或多个心肌节段，心肌厚度≥15㎜)。超声心动图检查在评价和定量心室壁的增厚，评估二尖瓣前叶收缩期前向运动(SAM现象)，潜在的左心室流出道梗阻(LVOTO)等方面有重要的作用。但是，常规超声心动图不能对早期的心肌损害和早期的鉴别诊断进行准确判断。 新颖的超声心动图新技术，如血流向量成像(VFM)、二维斑点分层应变技术和三维斑点追踪技术(3DSTI)等成为了全方位评价心脏整体和节段功能的新方法。VFM技术可以对心腔内的血流动力学状况，如循环、能量损耗、室壁剪应力等参数进行评价。二维斑点分层应变技术可以对心内膜、中层、心外膜各层心肌的早期收缩功能和同步性进行评价。三维斑点追踪技术对心肌进行三维应变收缩功能和扭转功能的评价。 这些新颖的心脏超声方法正逐步成为临床检查的关键工具，让我们有效的改进了对肥厚型心肌病(HCM)的诊断的方法。 研究分为三个部分： 第一部分：血流向量成像(VFM)对肥厚型心肌病患者左心室能耗和室壁剪切力的评价 目的：运用血流向量成像(VFM)的方法评价肥厚型心肌病患者左心室总能耗(EL-SUM)，平均能耗(EL-AVE)，室壁剪切应力(WSS)。 方法：对40例肥厚型心肌病患者，40例对照组进行经胸超声心动图的检查。分别测量常规超声参数，心脏在不同时相，总能耗和平均能耗(EL-total，EL-base， EL-mid， EL-apex)，以及每个节段的WSS。 结果：和对照组相比，肥厚型心肌病组(HCM)常规舒张期指标受损。HCM组在左心室的快速射血期(T2)左心室总能耗(EL-SUM)，平均能耗(EL-AVE)增加。在舒张早期结束时(T4)，左心室总能耗(EL-SUM)，平均能耗(EL-AVE)降低。在对照组，左心室总能耗(EL-SUM)，平均能耗(EL-AVE)从基底到心尖逐渐降低，而HCM患者没有此规律。和对照组相比，HCM组在左心室快速射血期(T2)和房缩期(T5)，WSS增加；在舒张早期结束时(T4)，WSS降低(P＜0.05)。WSS在左心室峰值快速充盈期(T3)轻度增加(P=0.055)。 结论：血流向量成像(VFM)中的能量损耗(EL)，室壁剪切力(WSS)是新颖的血流动力学方法，可以有效的评估肥厚型心肌病患者收缩期和舒张期的血流动力学功能。 第二部分：二维斑点分层应变技术对肥厚型心肌病患者左心室收缩功能及同步性的评价 目的：应用二维斑点分层应变技术研究正常人及肥厚型心肌病患者的左心室长轴纵向、短轴径向三层(心内膜、中层、心外膜)心肌峰值应变及纵向应变达峰时间(PSD)改变的规律，探讨其临床应用价值。 方法：获取正常对照组(40例)、肥厚型心肌病组(40例)标准心尖四腔、三腔、两腔和短轴二尖瓣、乳头肌、心尖水平图像；分别测量和比较肥厚型心肌病组与正常对照组左心室长轴纵向、短轴径向三层(心内膜、中层、心外膜)心肌应变曲线及牛眼图，纵向应变达峰时间(PSD)。 结果：正常人及肥厚型心肌病(HCM)患者长轴四腔心、三腔心、两腔心切面及整体的心肌纵向应变，短轴二尖瓣平面、乳头肌平面、心尖平面及整体的心肌圆周应变呈由内层至中层、外层逐渐降低的过程(P值＜0.05)。与正常人相比，肥厚型心肌病(HCM)患者，四腔心、三腔心、两腔心切面及整体的内、中、外三层心肌纵向应变均降低，P值均＜0.01。据心肌纵向应变牛眼图分布可显示HCM患者心肌肥厚的部位，应变值降低的程度与心肌肥厚程度呈正相关，即心肌越肥厚的部位，应变值降低越多。与正常人相比，肥厚型心肌病(HCM)患者，心尖平面及整体的中、外层心肌心肌短轴圆周应变降低，P值＜0.01。与正常人相比，肥厚型心肌病(HCM)患者，左心室整体纵向应变降低(-20.44±1.58 vs-13.21±2.78，P＜0.01)，圆周应变降低(-17.99±3.18vs-14.08±1.93，P＜0.01)。正常对照组，左心室整体圆周应变跨壁应变阶差(ΔS=S〓-S〓)比纵向应变跨壁应变阶差变化明显(18.70±1.84vs5.74±0.71，P＜0.01)。与正常人相比，肥厚型心肌病(HCM)患者，左室18节段纵向应变达峰时间的标准差(PSD)增加(29.33±3.78 vs 83.77±34.34，P＜0.01)。 结论：二维斑点分层应变技术能够较好的评价肥厚型心肌病左室整体和局部的收缩功能。 第三部分：三维斑点追踪成像技术评价肥厚型心肌病患者的左室收缩功能及扭转 目的：应用三维斑点追踪成像技术研究正常人及肥厚型心肌病患者的左心室纵向应变、圆周应变、面积应变、径向应变，左心室扭转角度、扭矩等指标，探讨其临床应用价值。 方法：获取40例肥厚型心肌病组及40例正常对照组的三维全容积成像图像。分别测量左心室三维纵向应变，圆周应变，面积应变，径向应变和扭转角度，扭矩等力学参数。对两组间各参数结果进行对比和分析。 结果：与正常人相比，肥厚型心肌病患者左心室整体纵向应变(GLS)，面积应变(GAS)，径向应变(GRS)均降低，差异有统计学意义，P值＜0.01；圆周应变(GCS)降低，但差异无统计学意义(P值＞0.05)。与正常人相比，肥厚型心肌病患者左心室整体扭转角度峰值(Tw)增加(P值＜0.05)，差异有统计学意义。与正常人相比，肥厚型心肌病患者左心室二尖瓣平面旋转角度及心尖平面旋转角度峰值，左心室整体扭矩(RotB，RotA，Tor)增加(P＞0.05)，差异无统计学意义。与二维斑点追踪技术(2DSTI)相比，三维斑点追踪技术测量的纵向应变降低，圆周应变增加，径向应变增加，耗时明显减少。 结论：三维斑点追踪成像技术能够较好的评价肥厚型心肌病左心室收缩及扭转功能。 关键词：肥厚型心肌病 能量损耗 室壁剪切应力 血流向量成像 斑点分层应变技术 三维斑点追踪技术 纵向应变 圆周应变 径向应变 面积应变 扭转扭矩

 Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy with an age-related prevalence ranging from 0.02% to0.23% (ie, 1 in 500) in adults. In about 60% of cases, it is transmitted as an autosomal dominant trait mainly caused by mutations in cardiac sarcomere protein genes, while in a smaller proportion (5%—10%) of adult cases, HCM is caused by other genetic disorders (eg, inborn errors of metabolism, neuromuscular diseases, mitochondrial disease). Patients typically present with an increased left ventricular (LV) wall thickness, not otherwise explained by abnormal loading conditions. The anatomical and functional features include myocytes disarray, interstitial fibrosis, abnormal coronary microcirculatory function, and electrocardiographic abnormalities. The diagnosis of HCM is based on the detection of increased LV wall thickness (≥15 ㎜ in one or more LV myocardial segments) by any imaging modality. Standard echocardiographic examination represents a pivotal tool in prompt evaluation and quantification of LV wall thickness and identification of specific details, such as systolic anterior motion (SAM) of the mitral valve and latent LV outflow tract obstruction (LVOTO). However, it lacks diagnostic accuracy for the identification of early myocardial impairment and for differential diagnosis underlying this condition. The evolution of newer ultrasound-based technologies, such as vector flow mapping(VFM), 2D speckle tracking, 3D speckle tracking, has revolutionized the assessment of cardiac performance with a more sophisticated evaluation of global and regional cardiac function. VFM can evaluate the left ventricular hemodynamic status, such as left ventricular energy loss, wall shear stress and circulation, etc. Layer-specific quantification of myocardial deformation (subendocardial, midmyocardial, and subepicardial layer), may disclose the subclinical systolic dysfunction and synchronicity. 3D speckle tracking imaging can evaluate the systolic and twist function of left ventricle from the perspective of the three-dimensional. These advances are progressively becoming a pivotal tool in clinical workup of affected patients, allowing us to refine differential diagnosis in HCM. This research includes three parts: Part Ⅰ Left ventricular energy loss and wall shear stress assessed by vector flow mapping in patients with hypertrophic cardiomyopathy Objective: The aim of this study was to assess left ventricular (LV) summation of energy loss (EL-SUM), average energy loss (EL-AVE) and wall shear stress (WSS) using vector flow mapping(VFM) in patients with hypertrophic cardiomyopathy (HCM). Methods: Forty HCM patients, and 40 controls were evaluated by transthoracic echocardiography. Conventional echocardiographic parameters, summation and average of energy loss (EL-total, EL-base, EL-mid and EL-apex), and WSS in each segment were calculated at different phases. Results: Compared with controls, conventional diastolic measurements were impaired in HCM patients. HCM patients also showed increased EL-SUM-total and EL-AVE-total at the peak of LV rapid ejection period as well as decreased EL-SUM-total and EL-AVE-total at the end of early diastole. In controls, EL-SUM and EL-AVE showed a gradual decrease from the basal segment to the apex, this regularity was not observed in HCM patients. Compared with controls, HCM patients showed increased WSS at the peak of the LV rapid ejection period and the atrial contraction period as well as decreased WSS at the end of early diastole(all p＜0.05). WSS was increased slightly at the peak of the LV rapid filling period in HCM patients (p=0.055). Conclusion: EL and WSS values derived from VFM are novel flow dynamic parameters that can effectively evaluate systolic and diastolic hemodynamic function in HCM patients. Part Ⅱ Layer-specific quantification of myocardial deformation may disclose the subclinical systolic dysfunction and synchronicity in patients with hypertrophic cardiomyopathy Objective: To evaluate the global and regional myocardial systolic function in different myocardial layers and synchronicity in the patients with hypertrophic cardiomyopathy (HCM) by using layer-specific quantification of myocardial deformation. Methods: Myocardial imaging of 40 HCM patients (HCM group) and 40 healthy subjects (control group) was collected. The apical long-axis, four- and two-chamber views and parasternal short-axis at the basal, middle, apical levels were acquired by echocardiography. The peak systolic longitudinal and circumferential strain of the subendocardial, midmyocardial, and subepicardial layers was measured using two-dimensional speckle tracking echocardiography (2D STE). The standard deviation of time to peak longitudinal strain (PSD) in 18 segments of left ventricle were calculated. The data were compared and analyzed between the two groups. Results: The longitudinal and circumferential strain were decreased gradually from the subendocardial to the midmyocardial to the subepicardial layer in both HCM group and control group (p<0.05). Compared with healthy subjects, the absolute value of layer and global longitudinal strain was significantly lower in HCM group (p<0.01). The interventricular septum thickness at end-diastole positively correlated with the peak longitudinal systolic strain of the subendocardial, the midmyocardial, and the subepicardial layers from the bull-eye view of longitudinal myocardial strain. Compared with healthy subjects, the global circumferential strain and circumferential strain in apical level of midmyocardial and subepicardial layers was significantly lower in HCM group (p<0.01). Compared with controls, the global longitudinal and circumferential strain was significantly lower in HCM group (-20.44±1.58 vs -13.21±2.78,p<0.01;-17.99±3.18vs-14.08±l.93,p<0.01, respectively).The circumferential transmural gradient (ΔLS=LPSEndo- LPSEpi ) is obvious than the longitudinal transmural gradient (18.70±1.84v5.74±0.71s,P<0.01). PSD of HCM group was larger than that of control group (83.77±34.34 vs 29.33±3.78, P<0.01 ). Conclusion: Layer-specific quantification of myocardial deformation can assess left ventricular global and regional function, providing another useful equipment. Part Ⅲ Evaluation of systolic and twist function of left ventricle in hypertrophic cardiomyopathy using 3D speckle tracking imaging Objective: To evaluate the longitudinal, circumferential, area, radial strain and twist, torsion of left ventricle in the patients with hypertrophic cardiomyopathy (HCM) using 3D speckle tracking imaging . Methods: 4D full-volume imaging of 40 HCM patients (HCM group) and 40 healthy subjects (control group) was collected. Longitudinal, circumferential, area, radial strain and twist, torsion of left ventricle were measured respectively. The data were compared and analyzed between the two groups. Results: Compared with controls, the longitudinal strain, area strain, radial strain was significantly lower in HCM group (p<0.01, respectively). Circumferential strain was also lower in HCM group, but no significant difference was found between two groups(p>0.05). Compared with controls, left ventricular twist was significantly higher in HCM group (p<0.05). The rotation at the base and apex (RotB, RotA), torsion of left ventricular (Tor) in HCM group was higher, but no significant difference was found between two groups(p>0.05). Compared with 2D speckle tracking, the measurement of longitudinal was lower, circumferential strain and radial strain were higher using 3D speckle tracking. The measurement time was significantly reduced using 3D speckle tracking. Conclusion: 3D speckle tracking is a useful method to assess LV systolic function and torsional deformation and may make the assessment more available in clinical and research cardiology. Keywords: Hypertrophic cardiomyopathy, Energy loss, Wall shear stress, Vector flow mapping, Layer-specific speckle tracking, 3D speckle tracking, Longitudinal strain, Circumferential strain, Radial strain, Area strain, Twist, Torsion,