Erasmus MC Rotterdam, Cardiology, Postbus 2040, 3000, CA, Rotterdam, The Netherlands.
Erasmus MC Rotterdam, Biomedical Engineering, Rotterdam, The Netherlands.
Cardiovasc Ultrasound. 2020 Sep 29;18(1):40. doi: 10.1186/s12947-020-00222-1.
Shear waves are generated by the closure of the heart valves. Significant differences in shear wave velocity have been found recently between normal myocardium and disease models of diffusely increased muscle stiffness. In this study we correlate in vivo myocardial shear wave imaging (SWI) with presence of scarred tissue, as model for local increase of stiffness. Stiffness variation is hypothesized to appear as velocity variation.
Ten healthy volunteers (group 1), 10 hypertrophic cardiomyopathy (HCM) patients without any cardiac intervention (group 2), and 10 HCM patients with prior septal reduction therapy (group 3) underwent high frame rate tissue Doppler echocardiography. The SW in the interventricular septum after aortic valve closure was mapped along two M-mode lines, in the inner and outer layer.
We compared SWI to 3D echocardiography and strain imaging. In groups 1 and 2, no change in velocity was detected. In group 3, 8/10 patients showed a variation in SW velocity. All three patients having transmural scar showed a simultaneous velocity variation in both layers. Out of six patients with endocardial scar, five showed variations in the inner layer.
Local variations in stiffness, with myocardial remodeling post septal reduction therapy as model, can be detected by a local variation in the propagation velocity of naturally occurring shear waves.
心脏瓣膜关闭时会产生切变波。最近，在正常心肌和弥漫性肌肉僵硬增加的疾病模型之间，已经发现了切变波速度的显著差异。在这项研究中，我们将体内心肌切变波成像（SWI）与疤痕组织的存在相关联，作为局部僵硬增加的模型。假设僵硬的变化会表现为速度的变化。
10 名健康志愿者（第 1 组）、10 名未经任何心脏介入治疗的肥厚型心肌病（HCM）患者（第 2 组）和 10 名先前接受室间隔减少治疗的 HCM 患者（第 3 组）接受了高帧率组织多普勒超声心动图检查。在主动脉瓣关闭后，沿两条 M 型线在间隔的内层和外层绘制室间隔的 SW。
我们将 SWI 与 3D 超声心动图和应变成像进行了比较。在第 1 组和第 2 组中，没有检测到速度变化。在第 3 组中，8/10 名患者的 SW 速度出现变化。所有三名存在透壁疤痕的患者在两层均出现了同时的速度变化。在六名心内膜下疤痕患者中，有五名患者的内层出现了变化。
局部僵硬的变化，以室间隔减少治疗后的心肌重构为模型，可以通过自然发生的切变波传播速度的局部变化来检测。
