Dynamics Simulation Of Pulses Radial Of Electrical Field Controlled Spiral Waves In Two-dimensional Excitable Medium

Spiral waves in the heart are closely related to arrhythmia diseases such as tachycardia,ventricular fibrillation and cardiac sudden death,which has great harm to life and health.Therefore,it is of great practical significance to find a method to efficiently eliminate spiral waves in the heart.At present,the uniform electric field and circular polarization electric field methods based on wave emission from heterogeneities(WEH)theory have unique advantages in controlling efficiency and safety,and have attracted great attention recently.However,clinical implementation is still difficult due to the need for a global electric field.The research progresses of spiral waves controlling under various electric fields was reviewed in this paper.A new method of low-intensity to control spiral waves based on WEH theory was proposed,i.e.the pulses radial of electrical field(PREF)method.The method can efficiently control spiral waves by placing a needle-like electrode in the obstacle to emit PREF,including unpinning spiral waves,eliminating and suppressing the turbulent spiral waves.Through a series of numerical simulation,the dynamic process and internal mechanism were studied and analyzed.The main work of this paper is as following:(1)The dynamic model of PREF controlled spiral waves was established and resolved.An excitable system similar to the cardiac dynamics was constructed by using numerical simulation techniques.And anchored spiral waves were generated on the heterostructure(obstacles)in the medium to simulate the spiral wave electrical signals in the heart.Afterwards,a new PREF method and modeling idea were proposed,and the internal dynamic unpinning mechanism was expounded.The simulation results shown the unique advantage of the PREF method for unpinning that is not affected by the phase of spiral waves.(2)The numerical simulation of PREF spiral waves unpinning was carried out based on Barkley model.It is found that for single-armed spiral wave,the unpinning region of single pulses radial of electrical field(SPREF)is larger than that of a uniform electric field,and multiple pulses radial of electrical field(MPREF)can successfully unpin spiral waves in the entire parameter space.For multi-armed spiral waves,the success rate of unpinning is 100% for both SPREF and MPREF,and the intensity of MPREF unpinning can be as low as 1.05.And spiral waves can be completely removed by MPREF with appropriate parameters.Comparative studies have shown that the PREF method has many advantages,such as large unpinning area,high success rate and low electric field intensity.It is a better method for unpin spiral waves.(3)Based on the Bar-Eiswirth model,the control of spiral waves and its turbulent flow state was studied,such as unpinning,elimination and suppression of turbulence.The results show that PREF can successfully unpin spiral waves in the Bar-Eiswirth model.This shows that the PREF is not affected by the excitable medium model.And when the PREF frequency is 1.1-1.5 times spiral waves frequency,spiral waves in the medium can be completely driven out.In particular,we simulated the processes governing turbulence under the Bar-Eiswirth model and explained the intrinsic mechanism which PREF can control turbulence.The research shows that the PREF can suppress the turbulent state to generate the target wave: when the frequency of the electric pulse is slightly higher than the turbulent frequency,it can successfully suppress the turbulent spiral waves in the medium,and the electric field frequency does not exceed the maximum excitation frequency of the medium.The time required to suppress turbulence decreases as the frequency of the electric field increases.This study provides a new idea for efficiently eliminating spiral wave electrical signals in the heart,and provides a reference help for the development of electrophysiological experiments and clinical diagnosis and treatment of arrhythmia.