Reproducing Cardiac Ionic Model Properties Using a Discrete-Time Model
Rikhil L Seshadri1, Maxfield R Comstock1, Elizabeth M Cherry1
1School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Computing in Cardiology
|April 20, 2026
Summary
A new discrete-time cardiac model efficiently simulates cardiac action potentials (APs) and calcium dynamics. This computational approach offers advantages for studying long-term cardiac electrophysiology, like heart rate variability.
Area of Science:
- Computational Biology
- Cardiac Electrophysiology
- Mathematical Modeling
Background:
- Traditional differential equations models for cardiac action potentials (APs) are computationally intensive for long-term simulations.
- Studying phenomena like heart rate variability and cardiac remodeling requires efficient models.
Purpose of the Study:
- To develop and validate a discrete-time model for cardiac APs and intracellular calcium cycling.
- To establish correlations between continuous-time and discrete-time cardiac models.
Main Methods:
- Particle swarm optimization was used to parameterize the Qu et al. discrete-time model.
- The discrete model was fitted to action potential duration (APD) data from ten Tusscher et al. (2006), Beeler-Reuter, and Fox et al. continuous models.
- Model performance was evaluated across a range of pacing periods, including alternans regions.
Main Results:
- The discrete-time model successfully reproduced the APD dynamics of the tested continuous models.
- The discrete model captures key calcium dynamics, including peak intracellular calcium and sarcoplasmic reticulum calcium load.
- The discrete model requires a single update step per APD, offering significant computational savings.
Conclusions:
- A discrete-time cardiac model provides a computationally efficient alternative to detailed ionic models.
- This model can be used to study cardiac APs and calcium dynamics over long time scales.
- The validated discrete model facilitates research into heart rate variability and cardiac remodeling with reduced computational cost.
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