Badran Hala Mahfouz, Soliman Mahmood, Hassan Hesham, Abdelfatah Raed, Saadan Haythem, Yacoub Magdi
Cardiology Department, Menoufiya University, Egypt.
Glob Cardiol Sci Pract. 2013 Nov 1;2013(2):185-97. doi: 10.5339/gcsp.2013.25. eCollection 2013.
Right ventricular (RV) mechanics in hypertrophic cardiomyopathy (HCM) are poorly understood. We investigate global and regional deformation of the RV in HCM and its relationship to LV phenotype, using 2D strain vector velocity imaging (VVI).
100 HCM patients (42% females, 41 ± 19 years) and 30 control patients were studied using VVI. Longitudinal peak systolic strain (ϵsys), strain rate (SR), time to peak (ϵ) (TTP), displacement of RV free wall (RVFW) and septal wall were analyzed. Similar parameters were quantified in LV septal, lateral, anterior and inferior segments. Intra-V-delay was defined as SD of TTP. Inter-V-delay was estimated from TTP difference between the most delayed LV segment & RVFW.
ϵsys and SR of both RV & LV, showed loss of base to apex gradient and significant decline in HCM (p < 0.001). Deformation variables estimated from RVFW were strongly correlated with each other (r = 0.93, p < 0.0001). Both were directly related to LV ϵsys, SRsys, SRe, ejection fraction (EF)%, RVFW displacement (P < 0.001) and inversely related to age, positive family history (p < 0.004, 0.005), RV wall thickness, maximum wall thickness (MWT), intra-V-delay, LA volume (P < 0.0001), LVOT gradient (p < 0.02, 0.005) respectively. ROC curves were constructed to explore the cut-off point that discriminates RV dysfunction. Global and RVFW ϵsys: - 19.5% shows 77, 70% sensitivity & 97% specificity, SRsys: - 1.3s(- 1) shows 82, 70% sensitivity & 30% specificity. Multivariate analyses revealed that RVFW displacement (β = - 0.9, p < 0.0001) and global LV SRsys (β = 5.9, p < 0.0001) are independent predictors of global RV deformation.
Impairment of RV deformation is evident in HCM using feature tracking. It is independently influenced by LV mechanics and correlated to the severity of LV phenotype. RVFW deformation analysis and global RV assessment are comparable.
肥厚型心肌病（HCM）患者右心室（RV）力学机制尚未完全明确。我们运用二维应变向量速度成像（VVI）技术，研究HCM患者右心室的整体及局部变形情况，以及其与左心室表型的关系。
采用VVI技术对100例HCM患者（女性占42%，年龄41±19岁）和30例对照患者进行研究。分析右心室游离壁（RVFW）和室间隔壁的纵向收缩期峰值应变（ϵsys）、应变率（SR）、达峰时间（ϵ）（TTP）以及位移。对左心室间隔、侧壁、前壁和下壁节段进行类似参数的定量分析。心室内延迟定义为TTP的标准差。心室间延迟通过最延迟的左心室节段与RVFW的TTP差值估算。
右心室和左心室的ϵsys及SR均显示基底到心尖梯度消失，且在HCM患者中显著下降（p<0.001）。由RVFW估算的变形变量彼此间高度相关（r = 0.93，p<0.0001）。两者均与左心室ϵsys、SRsys、SRe、射血分数（EF）%、RVFW位移直接相关（P<0.001），与年龄、家族史阳性分别呈负相关（p<0.004，0.005），与右心室壁厚度、最大壁厚度（MWT）、心室内延迟、左心房容积（P<0.0001）、左心室流出道梯度（p<0.02，0.005）呈负相关。构建ROC曲线以探索区分右心室功能障碍的临界点。整体及RVFW的ϵsys：-19.5%时，敏感性为77%、特异性为97%；SRsys：-1.3s(-1)时，敏感性为82%、特异性为70%、特异性为30%。多因素分析显示，RVFW位移（β = -0.9，p<0.0001）和整体左心室SRsys（β = 5.9，p<0.0001）是整体右心室变形的独立预测因素。
利用特征追踪技术可发现HCM患者右心室变形受损。其独立受左心室力学影响，并与左心室表型严重程度相关。RVFW变形分析与整体右心室评估具有可比性。
