Intrinsic dynamics of heart regulatory systems on short time-scales: from experiment to modelling

TL;DR

This paper investigates the short-term stochastic dynamics of heart rate variability, demonstrating it behaves like Brownian motion and exploring simple models to replicate these experimental observations.

Contribution

It provides experimental evidence of HRV's diffusive nature on short time scales and discusses open challenges in modeling heart control systems.

Findings

HRV exhibits free diffusion on sub-minute time scales

HRV can be modeled as a non-stationary process with stationary increments

Open problems identified in modeling heart dynamics

Abstract

We discuss open problems related to the stochastic modeling of cardiac function. The work is based on an experimental investigation of the dynamics of heart rate variability (HRV) in the absence of respiratory perturbations. We consider first the cardiac control system on short time scales via an analysis of HRV within the framework of a random walk approach. Our experiments show that HRV on timescales of less than a minute takes the form of free diffusion, close to Brownian motion, which can be described as a non-stationary process with stationary increments. Secondly, we consider the inverse problem of modeling the state of the control system so as to reproduce the experimentally observed HRV statistics of. We discuss some simple toy models and identify open problems for the modelling of heart dynamics.