Redaelli Alberto, Maisano Francesco, Soncini Monica, Alfieri Ottavio, Montevecchi Franco Maria
Department of Bioengineering, Politecnico di Milano, Via Golgi 39, 20133 Milan, Italy.
Med Eng Phys. 2004 Jan;26(1):31-42. doi: 10.1016/s1350-4533(03)00126-7.
Mechanics following partial left ventriculectomy is still poorly understood. A computational cylindrical model of the left ventricle was developed, based on the myocardial fibre behaviour for the evaluation of the mechanical and haemodynamical effects of the operation. A healthy left ventricle with physiological geometry and function and a dilated hypokinetic heart were investigated. Haemodynamic and mechanical data were obtained at baseline and compared with those obtained at different degrees of volume reduction. Data included: ejection fraction (EF); stroke volume (SV); end-systolic and end-diastolic pressure-volume relationships (ESPVR and EDPVR), and efficiency. EF increases following volume reduction in both simulation but, concurrently, SV shows modest improvement (dilated ventricle) or reduction (healthy ventricle) at progressive degrees of resection. The ESPVR and EDPVR slope increases and shifts leftward with the resection extent, but the increase of the ESPVR slope is more pronounced in dilated ventricle. Efficiency is improved in the dilated heart after resections, while does not improve when the healthy-heart volume is reduced. The simulation of partial left ventriculectomy suggests an improvement of systolic performance, counterbalanced by increased diastolic stiffness following inverse remodelling. Efficiency of simulated dilated ventricles is enhanced by volume reduction, suggesting a favourable effect of reduction of the metabolic demand of the failing heart.
部分左心室切除术的力学原理仍未得到充分理解。基于心肌纤维行为，建立了一个左心室的计算圆柱模型，用于评估该手术的机械和血液动力学效应。研究了具有生理几何形状和功能的健康左心室以及扩张性运动减弱的心脏。在基线时获取血液动力学和力学数据，并与不同程度体积减小后的相应数据进行比较。数据包括：射血分数（EF）；每搏输出量（SV）；收缩末期和舒张末期压力-容积关系（ESPVR和EDPVR）以及效率。在两种模拟中，体积减小后EF均增加，但同时，随着切除程度的增加，SV在扩张性心室中显示出适度改善，而在健康心室中则减小。ESPVR和EDPVR斜率随着切除范围的增加而增大并向左移动，但ESPVR斜率的增加在扩张性心室中更为明显。切除后扩张性心脏的效率得到改善，而健康心脏体积减小时效率并未提高。部分左心室切除术的模拟表明，收缩性能有所改善，但逆向重塑后舒张硬度增加起到了抵消作用。模拟扩张性心室的效率通过体积减小而提高，这表明减少衰竭心脏的代谢需求具有有利作用。
