The role of fine-scale anatomical structure in the dynamics of reentry in computational models of the rabbit ventricles
The role of fine-scale anatomical structure in the dynamics of reentry in computational models of the rabbit ventricles
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DOI：
10.1113/jphysiol.2012.229062
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发表时间：
2012-09-01
影响因子：
5.5
通讯作者：
Plank, Gernot
中科院分区：
文献类型：
--
作者：
Bishop, Martin J.;Plank, Gernot
心脏中的精细解剖结构可能在维持心律失常中起重要作用。然而，这种作用的程度以及它在物种之间的差异还没有完全了解。在这项研究中，我们使用计算模型来评估解剖结构对兔心室心律失常维持的影响。具体而言，我们量化了在模拟快速性心律失常和反复性心律失常发作期间激发波前的动态，定义为分别以相对低和高的时空紊乱为特征。使用了两种计算模型：高度解剖学详细的MR衍生兔心室模型（代表血管系统、内膜结构）和简化的等效模型，由相同的MR数据构建，但缺乏这种精细尺度的解剖特征。在快速性心律失常期间，解剖学上复杂和简化的模型显示出非常相似的动力学;然而，在快速性心律失常期间，随着激活波长降低，精细尺度解剖细节的存在似乎略微增加了复杂模型中心律失常期间波前的紊乱。尽管在随访分析中观察到内分泌结构周围的少量折返转子中心（细丝）聚集（随着转子尺寸减小，在纤颤期间略微增加），但这显著低于先前在大型动物中报告的情况。重要的是，在心律失常电影中没有明显可识别的折返转子锚定。心动过速和快速性心律失常之间的这些差异表明，折返转子相对于解剖障碍的相对大小决定了家兔室性心律失常维持中精细尺度解剖结构的影响。总之，我们的模拟结果表明，精细尺度的解剖特征在维持兔心室的快速性心律失常中起着很小的作用，与大型动物的实验报告相反，在维持快速性心律失常中似乎只起着很小的作用，这些发现也对优化心律失常调查中经常使用的解剖计算网格所需的细节水平具有重要意义。
Fine-scale anatomical structures in the heart may play an important role in sustaining cardiac arrhythmias. However, the extent of this role and how it may differ between species are not fully understood. In this study we used computational modelling to assess the impact of anatomy upon arrhythmia maintenance in the rabbit ventricles. Specifically, we quantified the dynamics of excitation wavefronts during episodes of simulated tachyarrhythmias and fibrillatory arrhythmias, defined as being respectively characterised by relatively low and high spatio-temporal disorganisation. Two computational models were used: a highly anatomically detailed MR-derived rabbit ventricular model (representing vasculature, endocardial structures) and a simplified equivalent model, constructed from the same MR-data but lacking such fine-scale anatomical features. During tachyarrhythmias, anatomically complex and simplified models showed very similar dynamics; however, during fibrillatory arrhythmias, as activation wavelength decreased, the presence of fine-scale anatomical details appeared to marginally increase disorganisation of wavefronts during arrhythmias in the complex model. Although a small amount of clustering of reentrant rotor centres (filaments) around endocardial structures was witnessed in follow-up analysis (which slightly increased during fibrillation as rotor size decreased), this was significantly less than previously reported in large animals. Importantly, no anchoring of reentrant rotors was visibly identifiable in arrhythmia movies. These differences between tachy- and fibrillatory arrhythmias suggest that the relative size of reentrant rotors with respect to anatomical obstacles governs the influence of fine-scale anatomy in the maintenance of ventricular arrhythmias in the rabbit. In conclusion, our simulations suggest that fine-scale anatomical features play little apparent role in the maintenance of tachyarrhythmias in the rabbit ventricles and, contrary to experimental reports in larger animals, appear to play only a minor role in the maintenance of fibrillatory arrhythmias.These findings also have important implications in optimising the level of detail required in anatomical computational meshes frequently used in arrhythmia investigations.