A compact multi-functional model of the rabbit atrioventricular node with dual pathways

Abstract

The atrioventricular node (AVN) is considered a “black box”, and the functioning of its dual pathways remains controversial and not fully understood. In contrast to numerous clinical studies, there are only a few mathematical models of the node. In this paper, we present a compact, computationally lightweight multi-functional rabbit AVN model based on the Aliev-Panfilov two-variable cardiac cell model. The one-dimensional AVN model includes fast (FP) and slow (SP) pathways, primary pacemaking in the sinoatrial node, and subsidiary pacemaking in the SP. To obtain the direction-dependent conduction properties of the AVN, together with gradients of intercellular coupling and cell refractoriness, we implemented the asymmetry of coupling between model cells. We hypothesized that the asymmetry can reflect some effects related to the complexity of the real 3D structure of AVN. In addition, the model is accompanied by a visualization of electrical conduction in the AVN, revealing the interaction between SP and FP in the form of ladder diagrams. The AVN model demonstrates broad functionality, including normal sinus rhythm, AVN automaticity, filtering of high-rate atrial rhythms during atrial fibrillation and atrial flutter with Wenckebach periodicity, direction-dependent properties, and realistic anterograde and retrograde conduction curves in the control case and the cases of FP and SP ablation. To show the validity of the proposed model, we compare the simulation results with the available experimental data. Despite its simplicity, the proposed model can be used both as a stand-alone module and as a part of complex three-dimensional atrial or whole heart simulation systems, and can help to understand some puzzling functions of AVN.

Atrioventricular nodal reentrant tachycardia onset, sustainability, and spontaneous termination in rabbit atrioventricular node model with autonomic nervous system control

“…The simulations were conducted with MATLAB R2023a, using its ode23 function to solve the ordinary differential equations. Other parameter values were similar to that in [9] and are based on rabbit experimental data [10, 11]. Additional details of the basic rabbit AV node model and its properties can be also found in [9].…”

“…Other parameter values were similar to that in [9] and are based on rabbit experimental data [10, 11]. Additional details of the basic rabbit AV node model and its properties can be also found in [9].…”

“…In the latter model, the authors modulate vagal tone by modifying parameters of AV node refractoriness and conduction velocity separately. Recently, we have developed a compact, multi-functional rabbit AV node model based on the simplified two-variable cardiac cell model [9]. The one-dimensional model includes dual pathways, primary pacemaking in the sinoatrial node (SN), and subsidiary pacemaking in SP and is tuned to the available experimental data.…”

Flexible Cell Modeling Using Frequency Modulation

“…Afterward, various other models like FitzHugh Nagumo (FHN) [10], Fenton Karma (FK) [9], Luo-Rudy-I (LR-I) [8], Beeler Reuter (BR) [27], Fabbri et al [11] and O'Hara [29] models, have expanded on the HH model in many spheres. There exist other cardiac cell models based on purkinje fibres [30][31][32][33], ventricular nodes [8,9,27,29] [ [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51], sinoatrial node [11] [52,53] and atrioventricular nodes [54]. These models have approximately 2-100 variables and many ordinary differential equations (ODEs).…”

Model-based estimation of AV-nodal refractory period and conduction delay trends from ECG

“…The AV node has previously been studied using several mathematical models based on invasive data from humans and animals Billette and Nattel (1994); Jørgensen et al (2002); Mangin et al (2005); Inada et al (2009); Climent et al (2011a); Masè et al (2012), Masè et al (2015); Ryzhii and Ryzhii (2023).…”