ABSTRAK
Electrophysiological properties of cardiac tissue change as a funktion of position. We define the "axcitability" as the propagaion velocity of an excitation pulse through the tissue, and study a simple FitzHugh-Nagumo (FHN) model of heart tissue whose excitability changes wit position. The propagation velocity is shown to be a good continuous measure of the excitabillity for both limit cycle and excitable tissues.