A bidomain model with periodic intracellular junctions: a one-dimensional analysis

Area of Science:

• Biophysics
• Computational Biology
• Cardiac Electrophysiology

Background:

• The classical bidomain model treats cardiac intracellular and extracellular spaces as separate continua.
• Accurate modeling of cardiac tissue is crucial for understanding electrical propagation and developing defibrillation strategies.

Purpose of the Study:

• To extend the classical bidomain model by introducing periodic intracellular conductivity to represent myocyte junctional discontinuities.
• To develop a novel spectral method for solving the governing equations of the extended bidomain model for finite tissue dimensions.

Main Methods:

• The study introduces a periodic conductivity in the intracellular space to model junctional regions with variable size and conductivity.
• A spectral technique combining finite Fourier integral transforms and Fourier series is employed to solve the coupled differential equations.
• The method is applied to a 50-cell, single interior fiber model under steady-state conditions to analyze defibrillation current response.

Main Results:

• The developed spectral method effectively solves the extended bidomain model equations.
• Calculations of transmembrane, intracellular, and extracellular potential distributions along the fiber were performed.
• The model allows for the examination of defibrillation current effects on cardiac tissue electrical properties.

Conclusions:

• The extended bidomain model with periodic intracellular conductivity provides a more realistic representation of cardiac tissue.
• The novel spectral method offers an efficient approach for simulating cardiac electrophysiology in finite tissue preparations.
• This work lays the foundation for further investigations into defibrillation mechanisms and optimization.