INFLUENCE OF ENDOCARDIAL-EPICARDIAL CROSSOVER OF MUSCLE-FIBERS ON LEFT-VENTRICULAR WALL MECHANICS
INFLUENCE OF ENDOCARDIAL-EPICARDIAL CROSSOVER OF MUSCLE-FIBERS ON LEFT-VENTRICULAR WALL MECHANICS
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DOI：
10.1016/0021-9290(94)90266-6
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发表时间：
1994-07-01
影响因子：
2.4
通讯作者：
RENEMAN, RS
中科院分区：
文献类型：
--
作者：
BOVENDEERD, PHM;HUYGHE, JM;RENEMAN, RS
用有限元模型模拟左心室的力学行为，研究了纤维方向的变化对左心室壁应力应变分布的影响。通常的螺旋纤维角被定义为局部周向方向与纤维路径在垂直于局部径向方向的平面上的投影之间的角度。在本研究中，一个额外的角度，横向纤维角，被用来模拟心室壁的内外层之间的肌纤维的连续过程。该角度被定义为纤维路径在垂直于局部纵向的平面上的投影与圆周方向之间的角度。首先，在心动周期期间进行左心室力学的参考模拟，其中横向角度被设置为零。接下来，我们进行了两次模拟，其中横向或螺旋角的空间分布相对于参考情况变化，空间平均变化分别为约3度和14度。纤维取向的变化几乎不影响心室的压力-容积关系，但显著影响主动肌纤维应力的空间分布（变化高达50%）和肌节长度（变化高达0.1 μ m）。在基底和顶端区域的壁，剪切变形在圆周-径向平面显着减少通过引入一个非零的横向角。因此，被动组织的负荷可以通过肌纤维的心内膜-心外膜交叉来减少。
The influence of variations of fiber direction on the distribution of stress and strain in the left ventricular wall was investigated using a finite element model to simulate the mechanics of the left ventricle. The commonly modelled helix fiber angle was defined as the angle between the local circumferential direction and the projection of the fiber path on the plane perpendicular to the local radial direction. In the present study, an additional angle, the transverse fiber angle, was used to model the continuous course of the muscle fibers between the inner and the outer layers of the ventricular wall. This angle was defined as the angle between the circumferential direction and the projection of the fiber path on the plane perpendicular to the local longitudinal direction.First, a reference simulation of left ventricular mechanics during a cardiac cycle was performed, in which the transverse angle was set to zero. Next, we performed two simulations in which the spatial distribution of either the transverse or the helix angle was varied with respect to the reference situation, the spatially averaged variations being about 3 and 14 degrees, respectively. The changes in fiber orientation hardly affected the pressure-volume relation of the ventricle, but significantly affected the spatial distribution of active muscle fiber stress (up to 50% change) and sarcomere length (up to 0.1 mu m change). In the basal and apical region of the wall, shear deformation in the circumferential-radial plane was significantly reduced by introduction of a nonzero transverse angle. Thus, the loading of the passive tissue may be reduced by the endocardial-epicardial crossover of the muscle fibers.