A time-varying elastance activation function captured the ventricular pressure-volume loop but produced an unrealistic atrial loop, while adjusting atrioventricular delay optimized atrial kick.
Computational models of the cardiovascular system exhibit varying fidelity in simulating atrioventricular dynamics, highlighting the need to select appropriate models based on the specific physiological parameters being studied.
Cardiovascular models have been developed for disease diagnosis support, the study of cardiovascular physiology, and design optimization of prosthetic devices. However, the wide variety of models can make comparison difficult. This review provides an overview of cardiovascular system models and compares three representative models, based on coupled systems of ordinary differential equations to reproduce hemodynamics implemented within Simulink. The analysis focuses on the model fidelity and capability, in terms of atrial contractility and the activation function of the heart contraction, which have been implemented either only partially or not at all in the original papers. Simulation results revealed that the effect of an atrial kick was neglected in the passive atria model, assuming a linear relationship between the atrium pressure and volume, thereby limiting its ability into a low range of heart rate. A time-varying elastance activation function captured the ventricular pressure–volume (PV) loop but produced an unrealistic atrial PV loop while the inverse was the case for a time-varying pressure model. Adjusting an atrioventricular delay (AVd) is achievable in the contractile atria model, revealing that the optimal AVd is a trade-off between the atrial filling and contraction to maximize the effectiveness of atrial kick to assist complete ventricular filling.
Ryu et al. (Mon,) conducted a review in Cardiovascular physiology modeling. Lumped parameter models of the cardiovascular system was evaluated on Model fidelity and capability in terms of atrial contractility and activation function. A time-varying elastance activation function captured the ventricular pressure-volume loop but produced an unrealistic atrial loop, while adjusting atrioventricular delay optimized atrial kick.