Abstract
Due to the experimental limitations in studying human heart functions, the use of computer simulation is becoming more and more important. However, research on the contraction model of the ventricular cell and propagation model of the excitation wave have mainly been studied independently despite the fact that myocardial excitation—contraction coupling is fundamental to the heart function. In this article, an excitable contraction model of ventricular tissue cable is constructed to study the effect of different stimulating patterns on tissue contraction. The contraction force for each element is calculated based on an electro-physiological ventricular cell model (Kyoto Model). The mechanical deformation of tissue is solved using the finite element method. The electrophysiological calculation and mechanical calculations are coupled to obtain a simulation reflecting the force-length relation of the myocardial cell. Several factors such as the starting point and conduction velocity of stimulation signals affect contraction behavior. Here, we show that the activation time (AT), which is the time the stimulation signal needs to spread over the tissue, is a dominant indicator for determining the tissue contraction force. When AT decreases, the tissue contraction force increases monotonically. This fact suggests that the minimization of AT could be an important clue for achieving effective tissue contraction. Furthermore, the effect of increasing stimulating points has been analyzed. Simulation data suggests the importance of the number and position of pacing leads to improve the pump function of a failing heart in cardiac resynchronization therapy such as biventricular pacing.
