Identifying locations susceptible to micro-anatomical reentry using a spatial network representation of atrial fibre maps

Abstract

Micro-anatomical reentry has been identified as a potential driver of atrial fibrillation (AF). In this paper, we introduce a novel computational method which aims to identify which atrial regions are most susceptible to micro-reentry. The approach, which considers the structural basis for micro-reentry only, is based on the premise that the accumulation of electrically insulating interstitial fibrosis can be modelled by simulating percolation-like phenomena on spatial networks. Our results suggest that at high coupling, where micro-reentry is rare, the micro-reentrant substrate is highly clustered in areas where the atrial walls are thin and have convex wall morphology, likely facilitating localised treatment via ablation. However, as transverse connections between fibres are removed, mimicking the accumulation of interstitial fibrosis, the substrate becomes less spatially clustered, and the bias to forming in thin, convex regions of the atria is reduced, possibly restricting the efficacy of localised ablation. Comparing our algorithm on image-based models with and without atrial fibre structure, we find that strong longitudinal fibre coupling can suppress the micro-reentrant substrate, whereas regions with disordered fibre orientations have an enhanced risk of micro-reentry. With further development, these methods may be useful for modelling the temporal development of the fibrotic substrate on an individualised basis.

Systematic in-silico evaluation of fibrosis effects on re-entrant wave dynamics in atrial tissue

“…The accuracy of LA activation maps produced by a fibre-independent isotropic models with tuned diffusion coefficients was proven high (i.e., 96% for focal and 93% for rotor arrhythmias) and consistent with a model incorporating myocardial fibres with the same geometry 29 . The dependence of AF driver location on atrial fibre field further decreased in the presence of fibrotic remodelling and electrical heterogeneity, when the micro re-entrant substrate became more spatially variegated 61 . These studies partially support the use of an isotropic monolayer in our study and the validity of our results to reproduce functional re-entry dynamics in the LA.…”