Okada Kazunori, Yamada Satoshi, Iwano Hiroyuki, Nishino Hisao, Nakabachi Masahiro, Yokoyama Shinobu, Abe Ayumu, Ichikawa Ayako, Kaga Sanae, Nishida Mutsumi, Hayashi Taichi, Murai Daisuke, Mikami Taisei, Tsutsui Hiroyuki
Faculty of Health Sciences, Hokkaido University.
Circ J. 2015;79(11):2471-9. doi: 10.1253/circj.CJ-15-0646. Epub 2015 Sep 8.
Although longitudinal strain (LS) is known to be reduced in patients with hypertrophic cardiomyopathy (HCM), it has not been elucidated whether or not circumferential strain (CS) is reduced. We aimed to determine whether multidirectional and layer-specific myocardial strain is reduced in patients with nonobstructive HCM.
Speckle-tracking echocardiography was performed in 41 HCM patients and 27 control subjects. Segmental and global LS and CS were measured in the inner, mid, and outer layers. Global LS was significantly lower in the HCM group than in controls in the inner (-10.3±2.9 vs. -14.8±2.0%, P<0.001), mid (-8.7±2.6 vs. -13.8±1.9%, P<0.001), and outer (-7.2±2.6 vs. -11.9±1.9%, P<0.001) layers. Global CS was preserved in the inner layer (-23.8±4.7 vs. -24.3±3.3%, P=0.69) but reduced in the mid (-10.3±3.1 vs. -13.3±2.5%, P<0.001) and outer layers (-6.7±2.3 vs. -8.6±2.3%, P=0.002). Differences in CS between the inner and outer layers correlated with segmental relative wall thickness (r=-0.20, P=0.002). Furthermore, only the absolute value of global CS in the inner layer positively correlated with left ventricular ejection fraction (r=0.32, P<0.01) among these multidirectional and layer-specific strains.
In patients with HCM, not only the LS in all layers but also CS in the mid and outer layers was reduced, presumably reflecting impaired myocardial function. In contrast, CS in the inner layer was preserved, being associated with maintenance of chamber function.
尽管已知肥厚型心肌病（HCM）患者的纵向应变（LS）降低，但圆周应变（CS）是否降低尚未阐明。我们旨在确定非梗阻性HCM患者的多方向和层特异性心肌应变是否降低。
对41例HCM患者和27例对照者进行斑点追踪超声心动图检查。在内层、中层和外层测量节段性和整体LS及CS。HCM组内层（-10.3±2.9对-14.8±2.0%，P<0.001）、中层（-8.7±2.6对-13.8±1.9%，P<0.001）和外层（-7.2±2.6对-11.9±1.9%，P<0.001）的整体LS显著低于对照组。内层的整体CS得以保留（-23.8±4.7对-24.3±3.3%，P=0.69），但中层（-10.3±3.1对-13.3±2.5%，P<0.001）和外层（-6.7±2.3对-8.6±2.3%，P=0.002）降低。内层和外层之间的CS差异与节段性相对壁厚度相关（r=-0.20，P=0.002）。此外，在这些多方向和层特异性应变中，仅内层整体CS的绝对值与左心室射血分数呈正相关（r=0.32，P<0.01）。
在HCM患者中，不仅所有层的LS降低，中层和外层的CS也降低，这可能反映了心肌功能受损。相比之下，内层的CS得以保留，与心室功能的维持有关。
