Recovery dynamics of the Fenton-Karma membrane model and their implications for modeling pharmacologically -induced atrial fibrillation

I used Continuity, a tool for finite element analysis, to model isotropic propagation of electrical activity based on the monodomain equation. I was able to induce action potential duration (APD) alternans, an important potential precursor to atrial fibrillation, and found that modulating several variables to mimic isoproterenol administration increased the slope of the restitution curve at low coupling intervals (25-75 ms). Meanwhile, mimicking the administration of ibutilide (by blocking the slow outward current in lieu of a potassium channel) actually increased the restitution slope, showing a limitation of this reductionist model. More work must be done in parameter optimization in order to deconvolve apparent restitution effects that are actually due to changes in the baseline action potential.