Critical fluctuations of the electrical activity of the heart: Shortcomings of models of excitability and interpretation

TL;DR

This paper presents evidence of critical fluctuations in the heart's electrical activity during atrial fibrillation, suggesting a phase transition mechanism involving disorder and chaotic patterns, challenging existing excitability models.

Contribution

It introduces the hypothesis that atrial fibrillation involves a phase transition with disorder, supported by evidence of scale invariance and long-range correlations in heart signals.

Findings

Evidence of scale invariance in heart potential during fibrillation

Long-range correlations observed in electrical activity

Disorder may arise from random modulation of gap junctions

Abstract

We report unexpected evidence of critical fluctuations of the electric potential of the heart during atrial fibrillation in humans. Scale invariance and long range correlations are found, which we show cannot be accounted for solely with the property of excitability, since disorder emerges by the formation of chaotic patterns in excitable media. To shed light on the data, we discuss the hypothesis that, in fact, fibrillation appears through a phase transition, which we compare on phenomenological grounds to a quenched-in disorder magnetic transition. We infer that, during propagation of pulses, random pinning might occur due to random modulation of the gap junction channels.