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The interrelations among stochastic pacing, stability, and memory in the heart
1Department of Biomedical Engineering, Faculty of Engineering, Tel-Aviv University, Tel-Aviv, Israel.
Biophysical Journal
|August 21, 2014
Summary
Stochastic pacing, or irregular heart rhythm, can prevent lethal arrhythmias by stabilizing heart tissue. However, excessive irregularity may increase action potential duration variance, potentially hindering its antiarrhythmic effect.
Area of Science:
- Cardiovascular Physiology
- Computational Biology
- Cardiac Electrophysiology
Background:
- Low pacing variability is linked to lethal cardiac arrhythmias.
- Previous simulations suggested stochastic pacing has antiarrhythmic effects by moderating action potential duration (APD) restitution and preventing wavebreaks.
Purpose of the Study:
- To elucidate the dynamic mechanisms linking pacing stochasticity to cardiac tissue stability.
- To establish the relationship between stochastic pacing, cardiac memory, and APD alternans.
Main Methods:
- Developed a mathematical framework using an autoregressive stochastic model for APD signals.
- Applied stability analysis tools to investigate the impact of pacing stochasticity on tissue stability.
- Analyzed the nonlinear, biphasic modulation of memory coefficients by pacing stochasticity.
Main Results:
- Increased stochasticity in ventricular activation sequences lowers maximal absolute eigenvalues, enhancing tissue stability.
- Pacing stochasticity nonlinearly modulates cardiac memory coefficients.
- Excessively high stochasticity can increase APD variance, potentially counteracting antiarrhythmic benefits.
Conclusions:
- Pacing stochasticity enhances cardiac stability by reducing eigenvalues, offering a potential antiarrhythmic mechanism.
- The relationship between stochasticity and cardiac memory is complex and biphasic.
- Further research is needed to define optimal stochastic pacing protocols to avoid increased APD variance.
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