Functional characterization of the p.Asp872Asn-SCN5A ultra rare variant identified in an unexplained SCA survivor with subtle inferior early repolarization. (A) Representative whole-cell tracings determined from a holding potential of −100 mV to testing potential of +90 mV in 10 mV increments with 24 ms duration. (B) Current–voltage relationship. (C) Steady-state inactivation curves. (D) Voltage-dependence of activation curves. (E) Recovery from inactivation from a holding potential of −120 mV to pre-pulse of −20 mV with 700 ms duration and with increased recovery interval followed by a test pulse of −20 mV with 20 ms duration. All values represent mean ± standard error of the mean. *P < 0.05 vs. SCN5A-WT. D872N, p.Asp872Asn-SCN5A ultra rare variant; G/Gmax, normalized conductance; I/Imax, normalized sodium current; SCA, sudden cardiac arrest; WT, wild type.