Summary of ion fluxes for WT, hyperKPP, and hypoKPP for elevation and reduction of K ⁺ . Shown graphically are the distinct, inappropriate ion fluxes caused by pathologic depolarizing currents in hyperKPP and hypoKPP. Both the size of arrows and the number of K⁺ and Na⁺ ions shown represent the magnitude of ion flux in each setting. Reduction in ion movement is depicted by thin, dotted line arrows and faint ions. NaP is persistent Na⁺ current, Kir is the inward rectifying K⁺ channel, and GP is the gating pore current. Andersen–Tawil syndrome is not included because the differences in K⁺ and Na⁺ influx and efflux compared with WT are small.