A Novel Human Atrial Electromechanical Cardiomyocyte Model with Mechano-Calcium Feedback Effect.

Electromechanical coupling is crucial for modeling a realistic representation of $Ca^{+2}$ transient and $Ca^{+2}$ cycling. Cellular $Ca^{+2}$ dynamics in atria differ fundamentally from the ventricles. A biophysically detailed electrophysiology model is hence necessary to reproduce the experimentally observed phenomena like $Ca^{+2}$ wave propagation in human atrial myocytes. In this work, we present a novel detailed and yet computationally efficient electrophysiology model, its coupling with a contraction myofilament model and the effect of mechano-calcium feedback on coupling. This novel electromechanical model was calibrated for a collection of human atrial data and was evaluated by reproducing the rate adaptation property of action potential, $Ca^{+2}$ transient and the active force. The aim of this article is to present a new electromechanical model for human atrial myocyte and to analyse the mechanism behind the rate adaptation.