What is the role of long QT syndrome in the etiology of ventricular tachycardia (VT)?

Updated: Dec 05, 2017
  • Author: Steven J Compton, MD, FACC, FACP, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Long QT syndrome is characterized by QT interval prolongation, T-wave abnormalities, and polymorphic VT. Persons with this syndrome are predisposed to episodes of polymorphic VT. These episodes can be self-limited, resulting in syncope, or they may transition into VF and thus can cause sudden cardiac death.

Long QT syndromes have been identified by eponyms (ie, Romano-Ward syndrome, Jervell and Lange-Nielsen syndrome, Andersen-Tawil syndrome, [24] and Timothy syndrome [25] ). The form sometimes known as Romano-Ward syndrome is the most common type. However, current practice is moving away from using eponyms and toward denoting these syndromes as numbered types (eg, LQT1 through LGT12) on the basis of identified underlying mutations.

Mutations in the KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 genes are known to be causative. Together, those five genes are responsible for virtually 100% of cases of inherited long QT syndrome.

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