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PubMed · 9785947

Virtual electrode effects in defibrillation.

N Trayanova·K Skouibine·P Moore
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Abstract

This modeling study demonstrates that a re-entrant activity in a sheet of myocardium can be extinguished by a defibrillation shock delivered via extracellular point-source electrodes which establish spatially non-uniform applied field. The tissue is represented as a homogeneous bidomain with unequal anisotropy ratios in the cardiac conductivities. Spiral wave re-entry is initiated in the bidomain sheet following an S1-S2 stimulation protocol. The results indicate that the point-source defibrillation shock establishes large-scale changes in transmembrane potential in the tissue (virtual electrodes) that are 'superimposed' over regions of various degrees of membrane refractoriness in the myocardium. The close proximity of large-scale shock-induced regions of alternating membrane polarity is central to the ability of the shock to terminate the spiral wave. The new wavefronts generated following anode/cathode break phenomena restrict the spiral wave and render the tissue too refractory to further maintain the re-entry. In contrast, shocks delivered via line electrodes establish, in close proximity to the electrode, changes in transmembrane potential that are of same-sign polarity. These shocks are incapable of terminating the re-entrant activation.

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AnisotropyArrhythmias, CardiacComputational BiologyElectric CountershockElectrodesEquipment DesignHeartHumansMembrane PotentialsModels, CardiovascularJournal Article

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BibTeXRIS

N Trayanova, K Skouibine, P Moore. 1998. Virtual electrode effects in defibrillation.. https://doi.org/10.1016/s0079-6107(98)00016-9

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