Causal Scale Shift Associated with Phase Transition to Human Atrial Fibrillation

TL;DR

This study investigates the causal architecture shift during the phase transition from normal sinus rhythm to atrial fibrillation in the human heart, revealing a significant change from macro to micro-scale causation.

Contribution

It introduces a novel multiscale causal analysis method using stochastic renormalization to understand heart rhythm phase transitions.

Findings

Causation shifts from macro to micro scales during AF transition.

Phase transition is associated with a peak causation change.

Method may apply to other complex systems' phase transitions.

Abstract

An example of phase transition in natural complex systems is the qualitative and sudden change in the heart rhythm between sinus rhythm and atrial fibrillation (AF), the most common irregular heart rhythm in humans. While the system behavior is centrally controlled by the behavior of the sinoatrial node in sinus rhythm, the macro-scale collective behavior of the heart causes the micro-scale behavior in AF. To quantitatively analyze this causation shift associated with phase transition in human heart, we evaluated the causal architecture of the human cardiac system using the time series of multi-lead intracardiac unipolar electrograms in a series of spatiotemporal scales by generating a stochastic renormalization group. We found that the phase transition between sinus rhythm and AF is associated with a significant shift of the peak causation from macroscopic to microscopic scales. Causal architecture analysis may improve our understanding of causality in phase transitions in other natural and social complex systems.