Drzewiecki G, Wang J J, Li J K, Kedem J, Weiss H
Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08855-0909, USA.
IEEE Trans Biomed Eng. 1996 Dec;43(12):1151-63. doi: 10.1109/10.544339.
Reversible mechanical dysfunction of the myocardium after a single or multiple episode(s) of coronary artery occlusion has been observed in previous studies and is termed myocardial stunning. The hypothesis that stunning could be represented by a decrease in maximum available muscle force in the stunned region was examined by means of a mathematical model that incorporates series viscoelastic elements. A canine experimental model was also employed to demonstrate depressed contractility and a consistent delay of shortening in the stunned region. The mechanical model of the left ventricle was designed to include a normal and stunned region, for which the stunned region was allowed to have variable size. Each region consisted of a volume and time dependent force generator in parallel with a passive elastic force element. The passive elastic element was placed in series with a constant viscosity component and a series elastic component. The model was solved by means of a computer. Passive and active properties of each region could be altered independently. The typical regional measures of muscle performance such as percent shortening, percent bulge, percent thickening, delay of shortening, percent increase in end-diastolic length and other hemodynamic measures were computed. These results were similar to those observed in animal models of stunning. In addition, a nearly linear relationship with end-diastolic length and delay of shortening was predicted by the model. It was concluded that a decrease in the peak isovolumic elastance and augmentation of viscosity effect of creep during stunning can explain mechanical abnormalities of stunned myocardium.
在先前的研究中已观察到单次或多次冠状动脉闭塞后心肌出现可逆性机械功能障碍，这被称为心肌顿抑。通过一个包含串联粘弹性元件的数学模型，检验了心肌顿抑可能表现为顿抑区域最大可用肌力降低的假说。还采用犬实验模型来证明顿抑区域的收缩力降低和缩短持续延迟。左心室的力学模型设计为包括一个正常区域和一个顿抑区域，其中顿抑区域的大小可变。每个区域由一个与被动弹性力元件并联的随体积和时间变化的力发生器组成。被动弹性元件与一个恒定粘性成分和一个串联弹性成分串联放置。该模型通过计算机求解。每个区域的被动和主动特性可以独立改变。计算了肌肉性能的典型区域指标，如缩短百分比、隆起百分比、增厚百分比、缩短延迟、舒张末期长度增加百分比以及其他血流动力学指标。这些结果与在心肌顿抑动物模型中观察到的结果相似。此外，该模型预测了舒张末期长度与缩短延迟之间几乎呈线性关系。得出的结论是，心肌顿抑期间等容弹性峰值降低和蠕变粘性效应增强可以解释顿抑心肌的机械异常。
