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Stochastic Pacing Inhibits Spatially Discordant Cardiac Alternans

Dan Wilson1, Bard Ermentrout1

  • 1Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania.

Biophysical Journal
|December 7, 2017
PubMed

Insights

Reduced heart rate variability is linked to cardiac death. This study suggests that heart rate variability may protect against arrhythmias by reducing spatially discordant alternans through stochastic pacing.

Area of Science:

  • Cardiology
  • Computational Biology
  • Physiology

Background:

  • Depressed heart rate variability (HRV) is a known risk factor for sudden cardiac death in myocardial infarction survivors and congestive heart failure patients.
  • The proarrhythmic role of reduced HRV remains unclear, with debate on whether it directly causes arrhythmias or reflects autonomic dysfunction severity.

Purpose of the Study:

  • To investigate a potential mechanism by which heart rate variability (HRV) might protect against cardiac arrhythmias.
  • To explore the relationship between stochastic pacing variance and the occurrence of spatially discordant alternans.

Main Methods:

  • Numerical simulations were employed to model cardiac electrophysiology.
  • Analysis focused on factors including conduction velocity restitution, cellular dynamics, electrotonic coupling, and stochastic pacing.
  • The study examined the nodal dynamics of spatially discordant alternans.

Main Results:

  • An inverse relationship was observed between the variance of stochastic pacing and the incidence of spatially discordant alternans.
  • This finding suggests that increased variability in pacing may inhibit the development of this proarrhythmic state.

Conclusions:

  • Heart rate variability may offer protection against cardiac arrhythmias, specifically by mitigating spatially discordant alternans.
  • Understanding these dynamics can lead to novel control strategies for preventing arrhythmias.

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