FIG. 2.

Insights into mechanisms of ventricular arrhythmia initiation. (a) Investigating mechanisms of arrhythmia initiation. Decreasing pacing stimulus cycle length results in conduction slowing, increased alternans, and a steeper repolarization gradient, all of which creates an arrhythmogenic substrate for VA initiation. Reproduced with permission from Bayer et al., Heart Rhythm 13, 1922 (2016). Copyright 2016 Elsevier.⁴⁵ (b) Determining electrophysiological factors sufficient for VA initiation. In whole-heart swine models, VA could be initiated by infarct border zone model with fibrosis and decreased sodium conductance. Using an S1 and S2 pacing protocol, sustained re-entry was achieved. Reproduced with permission from Campos et al., Biophys. J. 117, 2361 (2019). Copyright 2019 Author(s), licensed under a Creative Commons Attribution (CC BY) license.⁴⁷