Baseline 12-lead ECGs obtained during the referral evaluation of SCN5A ultra rare variant-positive unexplained SCA survivors. (A) Representative 12-lead ECG from p.Glu30Gly-SCN5A-positive unexplained SCA survivor. (B) Representative 12-lead ECG from p.Gln245Lys-SCN5A-positive unexplained SCA survivor. (C) Representative 12-lead ECG from p.Pro648Leu-SCN5A-positive unexplained SCA survivor. (D) Representative 12-lead ECG from p.Asp872Asn-SCN5A-positive unexplained SCA survivor. (E) Representative 12-lead ECG from p.Glu1240Gln-SCN5A-positive unexplained SCA survivor. ECG, electrocardiogram; SCA, sudden cardiac arrest.