A simulation of the SA node by a phase response curve-based model of a two-dimensional pacemaker cells array.

Area of Science:

• Computational Biology
• Cardiac Electrophysiology
• Mathematical Modeling

Background:

• The sino-atrial (SA) node governs heart rhythm through the coordinated activity of pacemaker cells.
• Understanding SA node function requires modeling the complex interactions between individual cells.

Purpose of the Study:

• To develop and utilize a simplified two-dimensional model of the SA node to investigate pacemaker cell interactions.
• To explore how intrinsic cell properties and intercellular coupling affect SA node rhythm and electrical activity.

Main Methods:

• A two-dimensional array model of 15x15 pacemaker cells was employed.
• The model incorporated intrinsic cycle length and phase response curves (PRCs) to represent cell properties and interactions.
• Simulations analyzed spatial interactions, regional property variations, and electrical coupling effects.

Main Results:

• The model successfully simulated SA node activity, including activation patterns and conduction times.
• Regional variations in cell properties and coupling strength influenced the overall electrical behavior.
• A pseudo-electrocardiogram (ECG) signal was generated, demonstrating the model's ability to represent global SA node function.

Conclusions:

• A simplified physical-mathematical model using two fundamental pacemaker cell features (intrinsic cycle length and PRC) can effectively represent the SA node system.
• This approach provides insights into the genesis and maintenance of SA node activity.
• The model helps understand conditions leading to SA node instability and conduction disturbances.