Particle model describes chaotic spiral tips of atrial fibrillation with 100-fold boost in efficiency

Chaotic turbulence during atrial fibrillation poses major health risks and is thought to involve electrical wavefronts exhibiting spiral defect chaos. In this form of chaos, spiral tips are continuously created and annihilated, a phenomenon demonstrated in excitable media such as cardiac tissue. However, the high computational cost of solving large-scale reaction-diffusion systems has hampered simulations of this effect.

Tyree et al. developed a particle model that replicates spiral wave annihilation, providing a more efficient way to model spiral defect chaos. Using short-range attraction and diffusion and introducing a short-lived repulsive “kick” interaction between newly formed particle pairs, they reproduced termination statistics from real-world spiral chaos at a significantly lower computational cost.

“This paper delivers a fast, calibrated surrogate for spiral-wave turbulence that captures both annihilation and creation,” said author Wouter-Jan Rappel. “Instead of solving all variables in a spatially extended domain, the model applies simple rules to spiral tips, enabling exploration of arrhythmia termination across parameters and sizes that would be prohibitively slow with partial differential equations.”

The particle model yielded termination statistics in about one second, compared to over two minutes for previous methods. This hundred-fold speedup enables parameter sweeps, uncertainty quantification, and rare-event statistics across domain sizes. Specifically, it may accelerate drug discovery by linking ionic tissue changes to effective interaction parameters, thereby increasing spiral wave annihilation.

“Because the framework ties electrophysiological changes to effective interaction parameters, it offers a practical bridge from ionic and tissue physiology to fibrillation persistence versus self-termination, helping to prioritize classes of interventions,” Rappel said.

The group next looks to generalize the model to three-dimensional filament dynamics and to analyze rare events at scale.

Source: “Particle model of creation and annihilation captures termination dynamics of spiral defect chaos,” by Timothy J Tyree, Michael Reiss, and Wouter-Jan Rappel, Chaos (2025). The article can be accessed at https://doi.org/10.1063/5.0277113 .