KCNH2 and Sinus bradycardia: At present, permanent pacing is confined to neonates and infants with severe symptomatic bradyarrhythmia, either sinus bradycardia as seen in LQT1 or functional 2:1 AV block as occurs with homozygous LQT2 mutations or an LQT2 mutation in association with another mutation [13,14].