Characterization and Modeling of the Peripheral Cardiac Conduction System

Abstract

The development of biophysical models of the heart has the potential to get insights in the patho-physiology of the heart, which requires to accurately modeling anatomy and function. The electrical activation sequence of the ventricles depends strongly on the cardiac conduction system (CCS). Its morphology and function cannot be observed in vivo, and therefore data available come from histological studies. We present a review on data available of the peripheral CCS including new experiments. In order to build a realistic model of the CCS we designed a procedure to extract morphological characteristics of the CCS from stained calf tissue samples. A CCS model personalized with our measurements has been built using L-systems. The effect of key unknown parameters of the model in the electrical activation of the left ventricle has been analyzed. The CCS models generated share the main characteristics of observed stained Purkinje networks. The timing of the simulated electrical activation sequences were in the physiological range for CCS models that included enough density of PMJs. These results show that this approach is a potential methodology for collecting knowledge-domain data and build improved CCS models of the heart automatically.

An effective algorithm for the generation of patient-specific Purkinje networks in computational electrocardiology

“…In this respect, it is possible to consider one-dimensional Monodomain [31,22,19] and Bidomain [4] models. In particular, in [19] the effect of the Purkinje network on the cardiac resynchronization therapy has been investigated, whereas in [22] the authors extracted from images information about the morphology of the fibers. However, since we were interested in computing only the activation times in the network (in particular at the PMJ) and not the whole action potential, we considered again the Eikonal equation.…”

Automatic Location of Sources of Electrical Activation from Electroanatomical Maps

“…Terminal nodes at the deepest level of recursion are considered the PMJs. Branch lengths are generated following a normal distribution with parameters obtained from [8]. In this study we used three different levels of branch recursion, 2, 4 and 6.…”

“…Among the most common methods to build generic CCS for cardiac modelling there are: manual delineation of CCS branches, fractal models, segmentation of free-running sections from highresolution ex-vivo images, or stochastic rule-based CCS models constrained by population ex-vivo animal data [8]. Since it is not possible to obtain direct in-vivo imaging data from the CCS structure, the only related data available are the electrical measurements obtained by electro-anatomical mapping systems (EAMs).…”

Cardiac Arrhythmias: Mechanistic Knowledge and Innovation from Computer Models

“…In dissected hearts, PS fibers on the endocardium form a distinct network but 3D imaging of these structures remains difficult [109]; as such, another recent research trajectory has focused on the generation of anatomically re- alistic PS models that mimic the physiological network, which could provide insight on how interactions of myocardial tissue with the conduction system affect ventricular arrhythmia dynamics. Ijiri et al used fractal growth patterns to generate networks that qualitatively resembled the physiological PS [61].…”

“…Ijiri et al used fractal growth patterns to generate networks that qualitatively resembled the physiological PS [61]. Other groups have adapted this technique [28,109] to construct patient-specific PS models and explore how PS network complexity affects sinus activation sequence. It will be interesting to see what new insights on PS-mediated arrhythmia dynamics can be gained from simulations that incorporate PS models with increased geometric complexity, which are now a possibility.…”