Computational analysis of Head-Down Bed Rest effects on cardiac action potential duration

Several episodes of ventricular arrhythmias have been reported during spaceflights, and cardiovascular deconditioning induced by microgravity exposure has already been assessed. Strict Head-Down Bed Rest (HDBR) can be used to simulate microgravity effects on the cardiovascular system. Therefore, it represents an invaluable opportunity to study and analyse this phenomenon. The aim of this work has been to evaluate the possible effect of blood electrolyte changes induced by 21 days of HDBR on the electrical activity of the heart, by using a computational model of human ventricular myocyte. Simulation results point out a biphasic course of action potential duration, which shortened during HDBR and recovered after the end of it, accordingly with RT interval measurements from ECG data analysis.