Instability of spiral and scroll waves in the presence of a gradient in the fibroblast density: the effects of fibroblast-myocyte coupling

TL;DR

This study explores how gradients in fibroblast density within cardiac tissue influence the stability of spiral and scroll waves, revealing that such gradients can induce instability and promote arrhythmogenic activity.

Contribution

The paper demonstrates that fibroblast density gradients destabilize spiral and scroll waves, highlighting the role of fibroblast-myocyte coupling in arrhythmia formation in fibrotic hearts.

Findings

GFD causes spiral and scroll wave instability.

Regions with varying wave frequency induce wave destabilization.

GFD can lead to spiral wave formation at high pacing frequencies.

Abstract

Fibroblast-myocyte coupling can modulate electrical-wave dynamics in cardiac tissue. In diseased hearts, the distribution of fibroblasts is heterogeneous, so there can be gradients in the fibroblast density (henceforth we call this GFD) especially from highly injured regions, like infarcted or ischemic zones, to less-wounded regions of the tissue. Fibrotic hearts are known to be prone to arrhythmias, so it is important to understand the effects of GFD in the formation and sustenance of arrhythmic re- entrant waves, like spiral or scroll waves. Therefore, we investigate the effects of GFD on the stability of spiral and scroll waves of electrical activation in a state-of-the- art mathematical model for cardiac tissue in which we also include fibroblasts. By introducing GFD in controlled ways, we show that spiral and scroll waves can be unstable in the presence of GFDs because of regions with varying spiral or scroll-wave frequency {\omega}, induced by the GFD. We examine the effects of the resting membrane potential of the fibroblast and the number of fibroblasts attached to the myocytes on the stability of these waves. Finally, we show that the presence of GFDs can lead to the formation of spiral waves at high-frequency pacing.