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Modelling and control of a failing heart managed by a left ventricular assist device

Son Jeongeun, Du Dongping, Du Yuncheng

Biocybernetics and Biomedical Engineering

2020

Vol. 40, no. 1

559--573

Left ventricular assist device (LVAD) recently has been used in advanced heart failure (HF), which supports a failing heart to meet blood circulation demand of the body. However, the pumping power of LVADs is typically set as a constant and cannot be freely adjusted to incorporate blood need from resting or mild exercise such as walking stairs. To promote the adoption of LVADs in clinical use as a long-term treatment option, a feedback controller is needed to regulate automatically the pumping power to support a time-varying blood demand, according to different physical activities. However, the tuning of pumping power induces suction, which will collapse the heart and cause sudden death. It is essential to consider suction when developing control strategy to adjust the pumping power. Further, hemodynamic of a failing heart exhibits variability, due to patient-to-patient heterogeneity and inherent stochastic nature of the heart. Such variability poses challenges for controller design. In this work, we develop a feedback controller to adjust the pumping power of an LVAD without inducing suction, while incorporating variability in hemodynamic. To efficiently quantify variability, the generalized polynomial chaos (gPC) theory is used to design a robust self-tuning controller. The efficiency of our control algorithm is illustrated with three case scenarios, each representing a specific change in physical activity of HF patients.

Lumped models of the cardiovascular system of various complexity

Ježek F., Kulhánek T., Kalecký K., Kofránek J.

Biocybernetics and Biomedical Engineering

2017

Vol. 37, no. 4

666--678

Purpose: The main objective is to accelerate the mathematical modeling of complex systems and offer the researchers an accessible and standardized platform for model sharing and reusing. Methods: We describe a methodology for creating mathematical lumped models, decomposing a system into basic components represented by elementary physical laws and relationships expressed as equations. Our approach is based on Modelica, an object-oriented, equation-based, visual, non-proprietary modeling language, together with Physiolibrary, an open-source library for the domain of physiology. Results: We demonstrate this methodology on an open implementation of a range of simple to complex cardiovascular models, with great complexity variance (simulation time from several seconds to hours). The parts of different complexity could be combined together. Conclusions: Thanks to the equation-based nature of Modelica, a hierarchy of subsystems can be built with an appropriate connecting component. Such a structural model follows the concept of the system rather than the computational order. Such a model representation retains structural knowledge, which is important for e.g., model maintainability and reusability of the components and multidisciplinary cooperation with domain experts not familiar with modeling methods.

Virtual instruments (VIs) in the study of cardiovascular and respiratory systems research

Clemente F., Ferrari G., De Lazzari C., Mimmo R., Guaragno M., Tosti G.

Biocybernetics and Biomedical Engineering

2003

Vol. 23, no. 2

17-26

The aim of this paper is to discuss problems (and solutions!) related to the design and the realisation of a system devoted to on line signal processing in different fields of engineering and applicable in cardiovascular and respiratory systems research and their interaction. A description of our approach is reported with some consideration of the hardware and software lay out. Different applications using our system have been described. These applications involve the use of a PC based system in clinical environment and in our laboratory on a mock circulatory system.