A rule‐based method to model myocardial fiber orientation in cardiac biventricular geometries with outflow tracts

Abstract

Rule‐based methods are often used for assigning fiber orientation to cardiac anatomical models. However, existing methods have been developed using data mostly from the left ventricle. As a consequence, fiber information obtained from rule‐based methods often does not match histological data in other areas of the heart such as the right ventricle, having a negative impact in cardiac simulations beyond the left ventricle. In this work, we present a rule‐based method where fiber orientation is separately modeled in each ventricle following observations from histology. This allows to create detailed fiber orientation in specific regions such as the endocardium of the right ventricle, the interventricular septum, and the outflow tracts. We also carried out electrophysiological simulations involving these structures and with different fiber configurations. In particular, we built a modeling pipeline for creating patient‐specific volumetric meshes of biventricular geometries, including the outflow tracts, and subsequently simulate the electrical wavefront propagation in outflow tract ventricular arrhythmias with different origins for the ectopic focus. The resulting simulations with the proposed rule‐based method showed a very good agreement with clinical parameters such as the 10 ms isochrone ratio in a cohort of nine patients suffering from this type of arrhythmia. The developed modeling pipeline confirms its potential for an in silico identification of the site of origin in outflow tract ventricular arrhythmias before clinical intervention.

Left sinus of Valsalva—Electroanatomic basis and outcomes with ablation for outflow tract arrhythmias

“…Furthermore, isolated fibers may exist that connect deeper sites to superficial exits. In fact, this heterogeneity in fiber orientation has been suggested in mathematical models as one potential reason for the genesis of PVCs arising from the outflow tracts 20 …”

“…In fact, this heterogeneity in fiber orientation has been suggested in mathematical models as one potential reason for the genesis of PVCs arising from the outflow tracts. 20 Thus, more than one limb of this region we have described as a The exact basis for why a variety of PVC morphologies could be effectively ablated from this region still requires elucidation. However, supravalvar myocardial fibers, remnants of the conduction system with their own insulation, and the cardiac skeleton may provide the necessary insulation from surrounding myocardium to create the potential for discrete but distant exits from the focus of an arrhythmia.…”

Predicting the Origin of Outflow Tract Ventricular Arrhythmias Using Machine Learning Techniques Trained With Patient-Specific Electrophysiological Simulations

“…Simulations were run using the data of 11 patients patients with idiopathic OTVAs submitted for ablation procedure at Hospital Clínic de Barcelona. Patient-specific biventricular models were generated from computed tomography CT images and using a fiber RBM specific to the OTs [4]. A total of 12 electrophysiological simulations were carried out in each geometry by changing the SOO according clinical reports [3].…”

Next-generation in-silico Cardiac Electrophysiology through Immersed Grid Meshfree Modelling: Application to Simulation of Myocardial Infarction

“…Myocardial fiber direction at the mesh vertices was generated using a rule-based method [10]. Moving Kriging interpolation was used to interpolate the fiber direction vectors from the vertices to the grid points ( Figure 2).…”