Cardiac Action Potential: Understanding the FitzHugh-Nagumo…

What is a Cardiac Action Potential?

A cardiac action potential refers to the rapid change in electrical charge across the cell membrane of a cardiac muscle cell (cardiomyocyte) during its contraction cycle. This process initiates with depolarization, followed by repolarization, and is essential for the coordinated beating of the heart.

The FitzHugh-Nagumo model provides a simplified yet powerful framework to describe these complex electrical phenomena in a two-dimensional space.

Introduction to the FitzHugh-Nagumo Model

Developed by Richard FitzHugh and J. Nagumo, this model is a set of differential equations that capture the essential features of excitable media like cardiac tissue. It consists of two coupled nonlinear ordinary differential equations representing the dynamics of membrane potential (v) and a recovery variable (w).

The model's simplicity allows for detailed analysis and simulation of complex behaviors such as spiral wave formation, which are critical in understanding arrhythmias.

live demo · related simulation● LIVE

How Does the Model Work?

In the FitzHugh-Nagumo model, the membrane potential (v) is influenced by a nonlinear function that describes the ionic currents through the cell membrane. The recovery variable (w) represents the slow processes within the cell, such as changes in intracellular calcium levels or other ion channels.

By adjusting parameters like diffusion, excitability, and recovery rates, one can simulate various physiological conditions and pathological states, providing insights into the mechanisms underlying cardiac arrhythmias.

Applications of the FitzHugh-Nagumo Model

The model has been widely used in both theoretical and experimental studies to understand the dynamics of excitable systems. It helps in predicting the onset of reentrant waves, which are responsible for many types of arrhythmias.

Moreover, it aids in designing new therapeutic strategies and drug targets by simulating how different interventions affect cardiac tissue behavior.

Frequently asked questions

What is a spiral wave in the context of cardiac action potentials?

A spiral wave refers to a rotating pattern of electrical activity that can form during an arrhythmia, often associated with ventricular tachycardia or fibrillation. It represents a self-sustaining wave front that spirals through the heart tissue.

How does adjusting the diffusion parameter affect the model?

Adjusting the diffusion parameter influences how quickly electrical signals spread across the cardiac tissue. Higher diffusion values allow for faster signal propagation, while lower values can lead to more localized activity patterns.

Why is excitability an important parameter in the model?

Excitability determines how easily a cell can be activated by external stimuli and plays a crucial role in determining whether a wave of electrical activity will propagate or not. Changes in excitability can lead to different types of arrhythmias.

Can the FitzHugh-Nagumo model predict real cardiac events?

While the model is highly simplified, it provides valuable insights into the basic mechanisms underlying cardiac electrical activity and can help predict certain aspects of cardiac behavior. However, for more accurate predictions, more complex models are necessary.

Try it live

Everything above runs in your browser — open Cardiac Action Potential: FitzHugh-Nagumo Excitable Media (2D) and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Cardiac Action Potential: FitzHugh-Nagumo Excitable Media (2D) simulation

Cardiac Action Potential: Understanding the FitzHugh-Nagumo Model