Synchronization-dissipation dynamics in the cardiorespiratory system

TL;DR

This paper investigates how synchronization between cardiac and respiratory rhythms reduces power dissipation in the heart's vasculature, suggesting a functional role for respiratory sinus arrhythmia in improving cardiac efficiency.

Contribution

It models the cardiorespiratory interactions to identify conditions for synchronization and demonstrates its role in reducing cardiac power losses across species.

Findings

Synchronization reduces cardiac power losses by up to 55% in some species.

Model predicts a 10% reduction in cardiac power loss in humans due to RSA.

Experimental pacing confirms the efficiency gains predicted by the model.

Abstract

Dissipative coupling is known to induce synchronization. Conversely it may be hypothesized that oscillators driven to synchronize may reduce power dissipation in their coupling. The latter scenario is realized in the human cardiorespiratory system where cardiac and respiratory rhythms are controlled by the central nervous system while interacting viscoelastically through the pulmonary vasculature. Here we examine the functional significance of this coupling which is observed in respiratory sinus arrhythmia (RSA). By modelling electrical and viscoelastic interactions within the cardiorespiratory system, we identify the conditions leading to synchronization. We demonstrate that, when present, synchronization reduces cardiac power losses by 10% in humans and up to 55% in other species. The predicted gain in cardiac output is compared to the gain observed in-vivo by pacing the heart with a device restoring RSA. It is therefore surmised that RSA may improve cardiac pumping efficiency by reducing dynamic stress and power dissipation in the pulmonary vasculature.