Mechanism underlying mechanical dysfunction in the border zone of left ventricular aneurysm: A finite element model study
Mechanism underlying mechanical dysfunction in the border zone of left ventricular aneurysm: A finite element model study
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DOI：
10.1016/s0003-4975(00)02338-9
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发表时间：
2001-02-01
影响因子：
4.6
通讯作者：
Pasque, MK
中科院分区：
文献类型：
--
作者：
Guccione, JM;Moonly, SM;Pasque, MK
背景资料。室壁瘤的整体左心功能障碍特征与等容收缩时邻近非梗死区(交界区)的肌纤维伸展有关。这种区域功能障碍的机制目前还不太清楚。成年多赛特绵羊冠状动脉结扎术造成心尖前壁穿壁心肌梗死，10周后形成左室壁室壁瘤。随后对动物进行磁共振成像，同时记录脑室内压。在舒张期充盈初期，利用多层短轴和长轴磁共振成像切片，建立了绵羊左心室前心尖部动脉瘤的三维数学模型。提出了三个模型模拟：(1)正常的边界区域收缩和正常的动脉瘤材料特性；(2)极大地降低边界区域的收缩(50%)和正常的动脉瘤材料特性；(3)极大地降低边界区域的收缩(50%)和硬化的动脉瘤材料特性(1000%)。只有后两种模拟能够再现实验观察到的等容收缩过程中交界区纤维的伸展。室壁瘤边缘区域机械功能障碍的机制主要是由于心肌收缩功能障碍，而不是该区域壁应力的增加。(C)2001年，由胸外科医生学会提供。
Background. The global left ventricular dysfunction characteristic of left ventricular aneurysm is associated with muscle fiber stretching in the adjacent noninfarcted (border zone) region during isovolumic systole. The mechanism of this regional dysfunction is poorly understood.Methods. An anteroapical transmural myocardial infarct was created by coronary arterial ligation in an adult Dorset sheep and was allowed to mature into left ventricular aneurysm for 10 weeks. The animal was imaged subsequently using magnetic resonance imaging with simultaneous recording of intraventricular pressures. A realistic mathematical model of the three-dimensional ovine left ventricle with an anteroapical aneurysm was constructed from multiple short-axis and long-axis magnetic resonance imaging slices at the beginning of diastolic filling.Results. Three model simulations are presented: (1) normal border zone contractility and normal aneurysmal material properties; (2) greatly reduced border zone contractility (by 50%) and normal aneurysmal material properties; and (3) greatly reduced border zone contractility (by 50%) and stiffened aneurysmal material properties (by 1000%). Only the latter two simulations were able to reproduce experimentally observed stretching of border zone fibers during isovolumic systole.Conclusions. The mechanism underlying mechanical dysfunction in the border zone region of left ventricular aneurysm is primarily the result of myocardial contractile dysfunction rather than increased wall stress in this region. (C) 2001 by The Society of Thoracic Surgeons.