Fig. 1From: Period doubling cascades of limit cycles in cardiac action potential models as precursors to chaotic early AfterdepolarizationsSimulation of Chaotic EADs. Numerical simulations of EADs using the deterministic AP models PP, PV and UP as outlined in the methods section. Model simulations were carried out for a time span of 2000 seconds, plots show short sections long after possible transients are gone. Positive largest Lyapunov exponents λ of the time series confirm the chaotic nature of the EADs. PP) Chaotic EADs, λ=4.7s −1, for the periodically forced pacemaker cell model PP with G K =0.04 mS/ cm2 as previously shown in [12]. For I sti we chose periodic step pulses with PCL = 1.075s, step duration d = 0.002s and step amplitude A = 42 μ A/cm2. PV) Chaotic EADs, λ=5.4s −1, for the periodically paced ventricular cell model PV with G K =0.282 mS/ cm2 as previously reported in [10]. For I sti we chose periodic step pulses with PCL = 0.7s, step duration d = 0.002s and step amplitude A = 30 μ A/cm2. As opposed to A), stimulation of the cell also takes place before full repolarization. UP) Chaotic EADs, λ=2.7s −1, for the unforced pacemaker cell model UP with G K =0.039218 mS/ cm2. Note that simulated chaotic EADs have previously only been published in context of periodic forcingBack to article page