ght The McGraw-Hill Companies, Ine Permission required for reproduction or display lonic mechanism Threshold 冷 Phase0:(lca 0.15 0.30 Time(s) Phase 3 100 口 Inactivation of L-type复 Pca?2+(L) Ca2+ channel A. PNa*(F) Pca2+m a Outward K+ current(k) 30 Time(s)Ionic mechanism ❖ Phase 0: ICa (ICa,L) ❖ Phase 3:  Inactivation of L-type Ca2+ channel  Outward K+ current (Ik )