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Nonlinear diffusion and thermo-electric coupling in a two-variable model of cardiac action potential
A Gizzi1, A Loppini1, R Ruiz-Baier2
1Department of Engineering, University Campus Bio-Medico of Rome, Unit of Nonlinear Physics and Mathematical Modeling, Via A. del Portillo 21, 00128 Rome, Italy.
Chaos (Woodbury, N.Y.)
|October 2, 2017
Summary
This study investigates cardiac action potential models with temperature effects and nonlinear diffusion. Findings show these factors influence wave repolarization and increase arrhythmia risk.
Area of Science:
- Computational Biology
- Biophysics
- Cardiovascular Physiology
Background:
- Cardiac tissue exhibits complex nonlinear dynamics crucial for normal heart function.
- Understanding factors influencing cardiac arrhythmias, such as spiral wave breakup, is vital for clinical applications.
Purpose of the Study:
- To theoretically investigate nonlinear dynamics and spiral wave breakup in a cardiac action potential model.
- To incorporate thermo-electric coupling and nonlinear diffusion into the model.
- To analyze the impact of temperature and nonlinear diffusion on cardiac electrophysiology and arrhythmogenesis.
Main Methods:
- Developed a generalized two-variable cardiac action potential model.
- Implemented thermo-electric feedback using Q10 and Moore factors.
- Formulated a nonlinear Fickian flux with a voltage-dependent diffusion coefficient (Taylor expansion).
- Performed numerical simulations on one-dimensional cables and two-dimensional grids.
Main Results:
- Thermo-electric coupling and nonlinear diffusion non-monotonically affect action potential repolarization.
- These factors were found to increase the propensity for spiral wave breakup and cardiac arrhythmias.
- Model parameters were tuned to match conduction velocity with equivalent cable models.
Conclusions:
- Nonlinear diffusion and temperature significantly alter cardiac electrophysiological properties.
- The developed model provides insights into the mechanisms underlying cardiac fibrillation.
- This research contributes to a better theoretical understanding of arrhythmia generation in cardiac tissue.
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