Key result
In a computer simulation model, lowering extracellular potassium concentration enlarged the temporal vulnerable window by increasing heterogeneity of Na channel conductance and modulating CV restitution.
Why the study?
Does low extracellular potassium increase arrhythmia vulnerability in a ventricular computer model?
Does low extracellular potassium increase arrhythmia vulnerability in a ventricular computer model?
Computer simulations demonstrate that low extracellular potassium increases arrhythmia vulnerability by enlarging the temporal vulnerable window and increasing transmural dispersion of refractoriness.
Answers are grounded in this paper and cite their sources.
Low K+ may heighten arrhythmia vulnerability in ventricular models; leaves clinical translation open pending experimental validation.
Unidirectional conduction block of cardiac excitation wave is one of the necessary conditions leading to initiation of reentrant arrhythmia. Temporal vulnerable window (VWtime) is an important measure for arrhythmia vulnerability. In this study, we examine theoretically how low extracellular K concentration ([K]o) control the VWtime by a single premature extrasystole. A numerical modified LR91 one dimensional heterogeneous ventricular model is used to quantitatively investigate the relation of low [K]o with conduction velocity (CV), VWtime, and electrical dynamic factor CV restitution. Morever, we characterize the distribution of Na channel conductance (gNa) and gating factors of premature beat applied at different time of the VWtime with different [K]o. The results show that lowering [K]o enlarge the VWtime magnitude gradually. The CV of S1 beat slows down with the [K]o in a reverse-[K]o dependent manner. Low [K]o promote the recovery of maximum Na conductance (GNa) from inactivation. However, decreasing [K]o can increase heterogeneity of gNa along the cable, and modulate CV restitution curve, which induce larger transmural dispersion of refratoriness for the premature beat and enlarge the VWtime.
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Cao et al. (2011) studied Cardiac Arrhythmia Vulnerability. Low extracellular potassium concentration ([K]o) vs. Different [K]o levels was evaluated on Temporal vulnerable window (VWtime) and conduction velocity (CV). In a computer simulation model, lowering extracellular potassium concentration enlarged the temporal vulnerable window by increasing heterogeneity of Na channel conductance and modulating CV restitution.
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