Key result
In a two-dimensional tissue model, bradycardia can unmask a slow endogenous pacemaker in a poorly coupled region, leading to spiral wave re-entry when steep and smooth coupling gradients are adjacent.
Why the study?
Does bradycardia in the presence of coupling heterogeneities induce spiral wave re-entry in a 2D tissue model?
Does bradycardia in the presence of coupling heterogeneities induce spiral wave re-entry in a 2D tissue model?
This computational study proposes a physiological mechanism for the spontaneous onset of re-entrant arrhythmias at normal or slow heart rates driven by structural coupling heterogeneities.
Answers are grounded in this paper and cite their sources.
Bradycardia with coupling heterogeneities may initiate re-entry; hypothesis-generating in 2D models, requiring in vivo validation before clinical consideration.
AIMS: The least understood aspect of re-entrant cardiac arrhythmias is how they start spontaneously. The known mechanisms for re-entry induction involve the application of premature electrical stimuli or rapid pacing, whereas in a clinical setting, re-entry often occurs at normal heart rates. Here, we propose a physiological mechanism of re-entry onset at normal and slow heart rates, which is based on structurally determined heterogeneities. METHODS AND RESULTS: Using a two-dimensional tissue model with Luo-Rudy II kinetics, we study electrical propagation in the presence of macroscopic coupling heterogeneities. We find that spiral wave re-entry occurs if steep and smooth coupling gradients are situated side by side, with the critical steepness depending on the frequency of stimulation. We demonstrate how bradycardia can unmask a slow endogenous pacemaker in a poorly coupled region, subsequently leading to spiral wave re-entry. CONCLUSION: In the presence of coupling heterogeneities, a single excitation coming from the less coupled region may induce spiral wave re-entry.
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Zemlin et al. (2007) studied Re-entrant cardiac arrhythmias. Macroscopic coupling heterogeneities and bradycardia was evaluated on Spiral wave re-entry. In a two-dimensional tissue model, bradycardia can unmask a slow endogenous pacemaker in a poorly coupled region, leading to spiral wave re-entry when steep and smooth coupling gradients are adjacent.
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