Cardiac Rhythm Phase 0 (Rapid Upstroke) Massive sodium inflow. Activated by -65 mV threshold Phase 1 (Early Repolarization) K+ efflux and cessation of Na+ inflow Phase 2 (Plateau) Diminution of most current flows Phase 3 (Late Repolarization) Inactivation of Ca++ flows and re-activation of Ka+ efflux Phase 4 (Diastolic Depolarization) Cardiac Conduction SA node is […]