Study of the Impact of Rectangular Current Pulses on the Ten Tusscher-Panfilov Model of Human Ventricular Myocyte

Abstract

The behavior of the 2006 ten Tusscher-Panfilov model of human ventricular myocytes under the impact of periodic excitation impulses was studied in the BeatBox simulation environment. The cardiomyocyte model has a limited susceptibility to an forced higher frequency excitation rhythm. A high-frequency excitation rhythm can be forced by gradually increasing the frequency of excitation impulses. The mechanism of defibrillation pulse impact consists of presumably prolonging the refractoriness of cardiomyocytes which undermines their susceptibility for a long time to a forced high-frequency rhythm of fibrillation, as a result for which they hinder the propagation of a fibrillation wave. This is the only mechanism of defibrillation that was identified during the simulation. The threshold energy of a depolarizing defibrillation pulse prolonging the refractoriness of the cardiomyocyte varies depending on a delay relative to the excitation impulse (the excitation cycle phase) in a wide range (the maximum value exceeds the minimum by several thousand times). The results show differences in the mechanisms of impact on a cardiomyocyte between an excitation impulse and a monophasic defibrillation pulse.

Areas of Effectiveness of Defibrillating Pulse in the Energy/Phase Diagram for the Fibrillation Cycle on the Cardiomyocyte Model

“…It was also confirmed on a two-dimensional model of the myocardium [6]. In the study [7] performed on the human ventricular cardiomyocyte model, energy/phase diagrams of the lower energy threshold of a rectangular depolarizing pulse extending its refractory period were constructed. The diagrams were constructed based on the assumption of the lower threshold only, i.e.…”

“…Imitation of fibrillation was caused by excitation impulses of 0.5ms duration with a frequency of 240min −1 (the limiting frequency, perceived by the model of a cardiomyocyte). The details of materials and methods are presented in [7].…”