Effect Of Myocardial Cell Memory On Spiral Wave Dynamics

Studies show that:heart disease is mainly caused by reentry arrhythmias in the atrium and ventricle (i.e. Reentrant tachycadia). Reentry arrhythmias includes atrial and ventricular tachycardia and ventricular fibrillation, and it is considered that the tachycardia is caused by the wave form of the target myocardium electrical signal propagation in the heart breaks which will become a spiral waves in some cases or even the chaotic state. Once cardiac ventricular fibrillation occurs, people may be in danger. Cardiac memory is a cardiac electrical remodeling phenomenon caused by changes of T wave vector. Research shows that cardiac memory is one of the reasons which lead to spiral wave phenomenon in the heart. In this paper, we will study is the effect of myocardial cell memory on dynamics of spiral waves which is based on the Greenberg-Hastings model (GH model), and purpose to find a way to eliminate the spiral wave in cardiac,provide a theoretical basis for the prevention or treatment of heart disease such as arrhythmia. This paper is organized as follows:The first chapter is the introduction. First of all, it will introduce the study of spiral wave dynamics, the organization of myocardial cells and memory, cellular automata and its GH model.The second chapter is based on the GH model, join the memory length m and random excitation probability p, establishment of a two-dimensional cellular automata in heart with memory,and simulate the effect of myocardial cell memory on spiral wave pattern and dynamics. The numerical simulation results show that:1. In the other parameters unchanged, changes to the value of p, the excitation of system will decreases with the increases of p, take the p control of a certain range (p>0.65), the spiral wave disappeared, it is show that the spiral wave can be eliminated by controlling the excitation of myocardial; 2. In the other parameters unchanged, changing the value of m, the excitation of system will increases with the increases of m, on the contrary, the excitation will decrease or even disappear with the decrease of m.The third chapter is changed action potential duration APD and memory cycles m/n, to research the effect of the stability of spiral waves. The numerical simulation results show that:1. In the other parameters unchanged, changing the value of APD, was founded the spiral waves will be increasingly unstable until the disappear with the increase of APD, it is provide a theoretical basis for eliminate the spiral wave; 2. In the other parameters unchanged, changing the memory length m, thus changing m/n, the excitation of the system increases with the increases of m/n. On the contrary, the excitation of system will be reduced or even disappear. When memory length increases, the spiral wave disappears slowly, and the memory length can be decreased, the spiral wave disappear more quickly, so as to achieve the purpose of rapid eliminate of the cardiac spiral waves.The fourth chapter is the summary of the second and the third chapters, and it gives further research observation.