An approximation model of myocardial crossbridge for weak coupling calculation of left ventricle model and circulation model.

It is necessary to use complicated myocardial cell model and heart model to evaluate the regional energy production and consumption which leads to the unrealistic computational time. In this research, a left ventricle (LV) simulation model was constructed which includes accurate myocardial cell model. In order to simulate the model in realistic time, we introduced an approximation model of the crossbridge model which can be calculated with weak coupling calculation.

Infant circulation model based on the electrophysiological cell model.

It is important to use a myocardial cell model to evaluate the effects of the drugs to the hemodynamic parameters. We developed an infant circulation model which incorporates an accurate myocardial cell model including a beta adrenergic system. The beta adrenergic system is essential mechanism for reproducing the response of baroreflex control system.

Fast drug action solving from cardiac action potential by model fitting in a sampled parameter space.

Model-based predictive approaches have been receiving increasing attention as a valuable tool to reduce cost in drug development. In this work, a model-fitting-based approach for solving drug actions using cardiac action potential recordings is investigated. Contribution of major ion currents in cardiac membrane excitation has been intensively studied.

Stress distribution in a rotationally symmetric and a measurement based left ventricular shape model.

We evaluated the stress distribution in a geometrical shape model and a shape model obtained from human heart using two different fiber orientations. For both orientation models, the results showed large differences of the stress distributions between the mathematical shape model and the measurement based shape model. These results suggest that stress distribution is highly dependent on the model geometry and the usage of a measurement based shape model is important for the evaluation of the left ventricular (LV) wall stress distribution.

Reproducing nonlinear force velocity relation of myocardial tissue by a nonlinear parallel elastic component.

To realize precise simulation of the left ventricular motion, it is important to utilize an accurate myocardial tissue model which can reproduce various characteristics of myocardial tissue contraction. In this study, we show that the nonlinear characteristics of the passive myocardial tissue property is the essential nature of the nonlinear force-velocity relation and present a formulation for hyperelastic physiological tissue property. Experimental results of our myocardial tissue simulation with the hyperelastic material property proposed are in good agreement with the reported force-velocity relation of real tissue.

The influence of activation time on contraction force of myocardial tissue: a simulation study.

The efficiency of heart pump function greatly depends on synchronized contraction of myocardial muscle. In this work, contraction simulation of an excitable ventricular tissue cable was constructed to study the influence of excitation patterns on tissue contraction. The tissue cable is composed of elements which contract when excited by an external stimulus.

Strong Coupling System for the LV Motion Simulation in a Distributed Simulation Environment.

A system where model parts can be easily exchanged and modified is of great advantage, especially in a combination of models such as an electrophysiological cell model and a mechanical model to a more complex left ventricular (LV) motion model. The use of a distributed simulation environment is straightforward because each simulation model is calculated by an existing user-friendly simulator. However, the weak coupling calculation usually used in a distributed environment reduces the accuracy of the simulation and results in an unstable simulation of the LV motion.