Simulation Study of the Arrhythmogenic Effects of Two Missense Mutations in Human Atrial Fibrillation

[EN] Genetic mutations affecting genes encoding for ion channel protein structures have been associated with the presence of atrial fibrillation (AF) in healthy individuals. The aim of this study is to model and simulate the effects of two gain-of-function mutations found in literature, T895M and T436M, and affecting the rapid delayed rectifier potassium current. Courtemanche human atrial model has been chosen to reproduce myocytes behaviour and an optimization algorithm has been employed to fit model parameters to experimental data. Single cell and tissue patch simulations have been performed to study the effects of the two mutations in control, paroxysmal and permanent AF conditions, both in right and left atrium. 0D simulations revealed that both mutations cause an increase in IKr current, leading to action potential duration shortening and flattening of restitution curves, especially in presence of the mutation T895M. Initiation of a re-entrant activity in 2D simulations were possible both in case of T895M and T436M. The study reports the arrhythmogenicity of the two mutants and reveals T895M having a stronger effect with respect to T436M, in particular in control rather than in paroxysmal and permanent AF conditions. Differences in the dynamics of the two mutations highlight the importance of a patient-specific approach in planning targeted drug therapies.