Fractional mathematical model Mcsherry

The article proposes a generalization of the McSherry mathematical model for modeling an artificial electrocardiogram — a time-varying signal that reflects the ion current that causes the heart fibers to contract and then relax. The generalization of the McSherry mathematical model consists in taking into account the property of heredity (memory) of the dynamic process, which can be described using fractional derivatives in the sense of Gerasimov-Caputo. The memory effect of a dynamic system determines the possibility of dependence of its states on the prehistory and may indicate the dissipative nature of the process under consideration. Further, using the theory of finite-difference schemes, an explicit finite-difference scheme of the first order of accuracy is constructed to find a numerical solution of the proposed model. With the help of the algorithm, the simulation results are visualized: oscillograms and phase trajectories are built for different values of the model parameters for a healthy person. The simulation results are interpreted. It is shown that the orders of fractional derivatives affect the dynamic modes of the considered fractional dynamical system. In the case of a commensurate fractional dynamical system, the limit cycle begins to collapse when the orders of the fractional derivatives are less than 0.5. In this case, the role of dissipation plays a significant role. In the case of an incommensurable fractional dynamical system, various regimes can arise from limit cycles to damped ones, and chaotic regimes are also possible. It was shown in the work that a chaotic regime arises at sufficiently large values of the angular velocity. The study of chaotic regimes deserves special attention and will be considered in the following articles. Also, the orders of fractional derivatives can be considered as additional degrees for the parameterization of ECG signals.