# Cardiac re-entry dynamics & self-termination in DT-MRI based model of Human Foetal Heart

## TL;DR

This study uses anatomically realistic DT-MRI based models of the human fetal heart to investigate how heart geometry and fiber anisotropy influence cardiac re-entry behavior and self-termination, revealing significant effects of anisotropy.

## Contribution

It introduces a novel simulation approach using DT-MRI data to analyze re-entry dynamics in fetal hearts, highlighting the impact of fiber anisotropy on re-entry stability and termination.

## Key findings

- Fiber anisotropy changes re-entry from pinned to anatomical in 2D slices.
- In 3D models, anisotropy leads to re-entry self-termination.
- Heart geometry influences re-entry dynamics significantly.

## Abstract

The effect of heart geometry and anisotropy on cardiac re-entry dynamics and self-termination is studied here in anatomically realistic computer simulations of human foetal heart. 20 weeks of gestational age human foetal heart isotropic and anisotropic anatomy models from diffusion tensor MRI data sets are used in the computer simulations. The fibre orientation angles of the heart were obtained from the DT-MRI primary eigenvalues. In a spatially homogeneous electrophysiological mono domain model with the DT-MRI based heart geometries, we initiate simplified Fitz-Hugh-Nagumo kinetics cardiac re-entry at a prescribed location in a 2D slice, and in the full 3D anatomy model. In a slice of the heart, the MRI based fibre anisotropy changes the re-entry dynamics from pinned to anatomical re-entry. In the full 3D MRI based model, the foetal heart fibre anisotropy changes the re-entry dynamics from a persistent re-entry to the re-entry self-termination.