Mock Circulation Loop Mathematical Model for Cardiac Assist Device Testing

The Mock Circulation Loop is a mechanical system designed to mimic the cardiovascular system in vitro. Its primary purpose is to conduct tests on various cardiovascular support devices. This becomes particularly crucial due to the insufficient availability of heart donations compared to the demand. In vitro testing using the MCL enables the anticipation of potential physiological scenarios, allowing the surgical team to practice by simulating critical situations that may arise, without causing harm to individuals. The MCL must accurately reproduce the pulsatile nature of the atria and ventricles, vascular resistance, fluid inertia, compliance of blood vessel walls, as well as pressure, flow, and volume of fluid. This study aims to develop a mathematical model of the MCL to identify optimal input parameters for assisting in the design and construction of a physical MCL in a Simulink/ MATLAB environment. To achieve this goal, equations have been formulated to divide the physical system into ten subsystems, representing the four heart chambers, systemic and pulmonary circulation for both arteries and veins, and two regulators to control ventricular contraction. Once the pressure and flow equations are derived, they are incorporated into the model alongside input parameters such as conduit and chamber lengths and diameters and regulators pressure. With the model established, conducting parameter variations becomes a straightforward task, enabling the execution of repetitive simulations to analyze the system frequency response across different scenarios, rest and heart failure. This iterative approach serves as a crucial step towards utilizing the mathematical model as a basis for constructing a physical Mock Circulation Loop.