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Abnormal excitation of the heart can cause cardiac arrhythmias, which may result in cardiac arrest and sudden cardiac death. Currently, the most efficient way to stop lethal cardiac arrhythmias is high-voltage defibrillation. This method is extremely effective. However, it has serious disadvantages, as it is painful and can damage the heart. In this paper, we studied in-silico process of overdrive pacing of arrhythmia sources, which in some cases can also stop cardiac arrhythmias and does not require the application of high voltages. We investigated this process in the Luo–Rudy ionic model for cardiac cells and in case of circular anisotropy of cardiac tissue. We showed that we could efficiently remove the arrhythmia sources in the form of rotating spiral waves in such a system in a certain parameter range. However, anisotropy by itself can cause additional dynamics of the spiral waves: drift and break up. We studied manifestations of these effects and discussed their possible effects on the overdrive pacing. This paper is an extended version of the paper [1] which was submitted to the ICCS 2018 conference proceedings.

Spiral waves in the heart underlie dangerous cardiac arrhythmias; therefore, methods of their elimination are of great interest. One way to do this is to remove the spiral waves using external high-frequency stimulation with a period smaller than that of the spiral. This type of treatment is called overdrive pacing and is an example of low-voltage cardioversion-defibrillation. It was studied in our recent works using a simple cardiac model proposed by Aliev and Panfilov. In this paper, we simulated low-voltage cardioversion using two biophysical models of the cardiac cells in an isotropic excitable square. We found stimulation periods that result in the effective removal of the spiral waves and measured the drift velocities induced by the stimulation. The effects of reducing of some ionic currents on this process were also investigated.

The low-voltage cardioversion-defibrillation is a modern sparing electrotherapy method for such dangerous heart arrhythmias as paroxysmal tachycardia and fibrillation. In an excitable medium, such arrhythmias relate to appearance of spiral waves of electrical excitation, and the spiral waves are superseded to the electric boundary of the medium in the process of treatment due to high-frequency stimulation from the electrode. In this paper we consider the Aliev–Panfilov myocardial model, which provides a positive tension of three-dimensional scroll waves, and an axisymmetric model of the left ventricle of the human heart. Two relations of anisotropy are considered, namely, isotropy and physiological anisotropy. The periods of stimulation with an apical electrode are found so that the electrode successfully entrains its rhythm in the medium, the spiral wave is superseded to the base of the ventricle, and disappears. The results are compared in two-dimensional and three-dimensional media. The intervals of effective stimulation periods are sufficiently close to each other in the two-dimensional case and in the anatomical model. However, the use of the anatomical model is essential in determination of the time of superseding.

The low-voltage cardioversion-defibrillation is a modern sparing electrotherapy method for such dangerous heart arrhythmias as paroxysmal tachycardia and fibrillation. In an excitable medium, such arrhythmias relate to appearance of spiral waves of electrical excitation, and the spiral waves are superseded to the electric boundary of the medium in the process of treatment due to high-frequency stimulation from the electrode. In this paper we consider the Aliev-Panfilov myocardial model, which provides a positive tension of three-dimensional scroll waves, and an axisymmetric model of the left ventricle of the human heart. Two relations of anisotropy are considered, namely, isotropy and physiological anisotropy. The periods of stimulation with an apical electrode are found so that the electrode successfully entrains its rhythm in the medium, the spiral wave is superseded to the base of the ventricle, and disappears. The results are compared in two-dimensional and three-dimensional media. The intervals of effective stimulation periods are sufficiently close to each other in the two-dimensional case and in the anatomical model. However, the use of the anatomical model is essential in determination of the time of superseding. © 2020 Walter de Gruyter GmbH, Berlin/Boston 2020. The work was supported by the Russian Science Foundation (project No. 17–71–20024). The work was performed with the use of the ‘URAN’ supercomputer of IMM UB RAS.

Spiral waves in the heart underlie dangerous cardiac arrhythmias such as fibrillation. Low-voltage defibrillation and cardioversion are modern methods to treat such pathologies. This type of electrotherapy is based on the phenomenon of superseding spiral waves by a high-frequency source of excitation. In this paper, we numerically simulated the superseding process in a thin layer of the cardiac muscle. We captured the case of a sole spiral wave with a stable core at the centre of a square. We used different cell-level models as well as a variety of electrode configurations and studied the induced drift of the spiral wave. Regimes of the external stimulation were classified based on whether they provide an effective and safe, that is without break-up, way to shift the spiral toward the boundary.