Table 1.

Clinical Characteristics in Common Genotypes of Congenital Long QT Syndrome

Gene mutedKCNQ1 (=KvLQT1)KCNH2 (=HERG)SCN5A
Current affectedIKsIKrINa
Events occurring with emotional stressStrong associationModerate associationWeak association
Events occurring with exerciseStrong associationWeak associationWeak association
Other triggersDivingLoud noiseSleep
Events before the age of 10 (%)40162
Events before the age of 40 (%)634618
Median age at first event (years)91216
Efficacy of β-blockade to prevent eventsStrong associationModerate associationWeak association
  • LQT, long QT subtype; IKs, slowly activating potassium-delayed rectifier; IKr, rapidly activating potassium-delayed rectifier; INa, cardiac voltage-dependent sodium channel.