FINITE-ELEMENT STRESS-ANALYSIS OF LEFT-VENTRICULAR MECHANICS IN THE BEATING DOG HEART
FINITE-ELEMENT STRESS-ANALYSIS OF LEFT-VENTRICULAR MECHANICS IN THE BEATING DOG HEART
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DOI：
10.1016/0021-9290(94)00174-3
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发表时间：
1995-10-01
影响因子：
2.4
通讯作者：
MCCULLOCH, AD
中科院分区：
文献类型：
--
作者：
GUCCIONE, JM;COSTA, KD;MCCULLOCH, AD
应用三维有限元模型探讨犬左室壁舒张末和收缩末期纤维应力从心尖到心底的分布是否均匀。在轴对称模型中加入了主动纤维应力的弹性模型，该模型精确地表示了前游离壁的几何形状和纤维角分布。静息心肌的非线性本构方程相对于局部纤维轴是横观各向同性的。舒张末纤维应力的跨壁分布从中脑室向心尖部或底部逐渐不均匀。在典型的舒张期左心室压力(1kPa)下，最大和最小纤维应力之差在中脑室附近仅为0.5kpa，而心尖部为4.6kpa，底部为3.3kpa。跨壁纤维应力差在收缩末期(14kPa)从底部到脑室中段(13~22kPa)相对较小，但在脑室中段和心尖部(30~43kpa)之间较大。所有六个三维舒张末应变分量都在或非常接近已发表的通过被动犬心脏左前中段游离壁的测量结果的一个标准差[Omens等人，amJ.Physiol.261、H918-H928(1991)]。收缩末期平面内正常应变和剪切应变也与发表的狗心跳动实验测量结果非常一致[Waldman等，Circ。决议63,550-562(1988)]。结果表明，与研究最充分的中脑室区域不同，正常左心室的纤维应力可能存在明显的区域不均匀，与形状和纤维角度的区域差异有关。
A three-dimensional finite element model was used to explore whether or not transmural distributions of end-diastolic and end-systolic fiber stress are uniform from the apex to the base of the canine left ventricular wall. An elastance model for active fiber stress was incorporated in an axisymmetric model that accurately represented the geometry and fiber angle distribution of the anterior free wall. The nonlinear constitutive equation for the resting myocardium was transversely isotropic with respect to the local fiber axis. Transmural distributions of end-diastolic fiber stress became increasingly nonuniform from midventricle toward the apex or the base. At a typical diastolic left ventricular pressure (1 kPa), the differences between largest and smallest fiber stresses were only 0.5 kPa near midventricle, compared with 4.6 kPa at the apex, and 3.3 kPa at the base. Transmural fiber stress differences at end-systole (14 kPa) were relatively small in regions from the base to the midventricle (13-22 kPa), but were larger between midventricle and the apex (30-43 kPa). All six three-dimensional end-diastolic strain components were within or very close to one standard deviation of published measurements through the midanterior left ventricular free wall of the passive canine heart [Omens et al., Am. J. Physiol. 261, H918-H928 (1991)]. End-systolic in-plane normal and shear strains also agreed closely with published experimental measurements in the beating dog heart [Waldman et al., Circ. Res. 63, 550-562 (1988)]. The results indicate that, unlike in the midventricle region that has been studied most fully, there may be significant regional nonhomogeneity of fiber stress in the normal left ventricle associated with regional variations in shape and fiber angle.