Development of transient outward K+ current to simulate ventricular action potentials of spontaneously hypertensive rats

We extended our adult rat ventricular myocyte model to formulate the effects of hypertrophy in spontaneously hypertensive rats (SHR). Membrane capacitance is increased by 53% and the density of transient outward current (I_t) is decreased by 35% in SHR but its voltage dependence and kinetics are unchanged when compared to those of normal rats. We simulated the ventricular action potential of SHR by incorporating these changes into our rat model. Action potential duration (APD) is prolonged when compared to that of normal rat. APD₉₀ (90% repolarization) and APD₅₀ (50% repolarization) of SHR are increased by 64% and 105% respectively when compared to those of normal rats. Peak overshoot of AP in SHR is increased by 7% and upstroke velocity is decreased by 6%.