Effects of preload, after-load and myocardial contractility on pressure-volume loop of the cardiovascular system model

Studies of cardiovascular system have been the hot point generally concerned as well as extraordinarily significant issue of bioscience. Because of the complexity of cardiovascular system, it is difficult to research the internal principle completely. Consequently, it is usual to study by modeling and simulation. In this article, the cardiovascular system model was established by using Matlab/Simulink. According to the functional test and the evaluation, the results of the model are highly similar to the clinical data, so it can be used widely to simulate various diseases and accidents. Based on the results, we mainly use the model to analyze the effective factors on pressure-volume loop of left ventricle, including preload, after-load and myocardial contractility. In a cardiac cycle, the pressure-volume (P-V) loop of left ventricle will always be in a series of dynamic changes. The pressure-volume relationship of left ventricle is a closed loop that could be used to evaluate the left ventricle's function. Preload, after-load and myocardial contractility always influence the cardiac outputs; the P-V loop will be changed as these factors change. The research focuses on the changes of these three factors and the corresponding changes of the P-V loop.