(A) APD90 among cells homozygous for the reference allele (C2-RR, n=23), heterozygous for R1193Q (C2-RQ, n=16), and homozygous for the R1193Q variant (C2-QQ, n=15). (B) The dofetilide concentration that prolonged APD90 by 100 ms ([Dof]Δ100ms) among C2-RR (n=6), C2-RQ (n=6), and C2-QQ (n=5). (C) Absolute change in APD90 at 10 nM dofetilide among C2-RR (n=6), C2-RQ (n=6), and C2-QQ (n=5).