A System Theoretic Oriented Model to Investigate the Dynamics Correlating Respiration and Hearth Rate Variability

Studying the interplay between respiration patterns and the heart rate variability (HRV) through mathematical models led to valuable insights into autonomic nervous system (ANS) functioning. Despite several models have been proposed in the literature, there is a lack of a general mathematical framework based on systems theory and formulated according to a rigorous control theory formalism. This work aims to reframe existing cardiopulmonary models into a general finite-dimensional nonlinear time-invariant (FDNTI) framework to capture respiration-cardiovascular interactions. A MATLAB Simulink-based implementation is presented and a simulation study is carried out. By exploiting control theory formalism, a system theoretic oriented model is obtained, which addresses roles of state variables, inputs, and linear/nonlinear contributions. Simulation tests confirmed the validity of the proposed modeling approach. This generalized formulation could enable in-depth analysis of physiological and pathological states by adopting advanced control theory techniques to investigate stability properties of the cardiorespiratory system.Clinical relevance- An in-silico model of respiration-cardiovascular interactions for assessing autonomic functioning.