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Cellular automaton model of ventricular fibrillation
R H Mitchell1, A H Bailey, J Anderson
1Department of Electrical and Electronic Engineering, University of Ulster, Co. Antrim, Northern Ireland.
IEEE Transactions on Bio-Medical Engineering
|March 1, 1992
Summary
This study models ventricular fibrillation using a cellular automaton. Increased excited state duration promotes chaotic microreentry, requiring stronger stimuli for defibrillation.
Area of Science:
- Cardiovascular Physiology
- Computational Biology
- Medical Physics
Background:
- Ventricular fibrillation (VF) is a life-threatening cardiac arrhythmia.
- Understanding the mechanisms of VF is crucial for developing effective defibrillation strategies.
- Current models often simplify the complex dynamics of cardiac electrical propagation.
Purpose of the Study:
- To theoretically analyze the requirements for ventricular fibrillation.
- To investigate the influence of excited state duration on fibrillation dynamics.
- To determine defibrillation thresholds based on fibrillation patterns.
Main Methods:
- A discrete element neighborhood (cellular automaton) model of ventricular conduction was employed.
- The model was configured as a 2500-element rectangular grid on a cylinder's surface.
- Simulations explored the relationship between excited state duration and reentry activity.
Main Results:
- Vulnerability to VF is strongly influenced by excited state duration.
- Increased excited state duration transitions VF from coarse macroreentry to fine microreentry.
- Defibrillation generally requires a stimulus to depolarize most relative refractory elements.
Conclusions:
- Excited state duration dictates the type of reentry activity in VF.
- Fine microreentrant fibrillation presents a higher defibrillation threshold.
- Cellular automaton models provide insights into VF mechanisms and defibrillation requirements.
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