Structural Differences in Transgenic Animals Associated with Atrial Fibrillation

The mechanisms that drive and sustain atrial fibrillation (AF) continue to be a highly researched topic. Atrial fibrosis has been linked with increased incidence of AF and conduction, but how fibrosis may lead to AF sustaining remains unknown. Our study aims to highlight heterogeneity in atrial fibrosis and how differences in fibrotic architecture may influence the sustainability of AF. In our study, we utilize a transgenic goat model with cardiac-specific over-expression of TGFβ-1 gene to examine structural differences of the fibrotic regions between animals that are inducible for AF and animals that remain AF-free. Our results indicate that there are structural differences between the fibrotic regions of AF inducible and non-inducible animals. Animals inducible for AF were found to have increased structural isotropy and increased fiber disarray within the fibrotic regions. Histology samples taken from the fibrotic regions showed fibrotic strands disrupted the tissue fibers in a more obstructive manner in the inducible animal group. These results highlight the heterogeneous differences of fibrotic regions.