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Prognosis and management of congenital long QT syndrome

Peter J Zimetbaum, MD
Charles I Berul, MD
Section Editors
John K Triedman, MD
Samuel Asirvatham, MD
Deputy Editor
Brian C Downey, MD, FACC


The long QT syndrome (LQTS) represents a diverse group of disorders of myocardial repolarization that is characterized by prolongation of the QT interval on the electrocardiogram (ECG). LQTS is important clinically because it is associated with an increased risk of a life-threatening form of polymorphic ventricular tachycardia called torsades de pointes (TdP) or "twisting of points" (waveform 1A-B), syncope and sudden cardiac death.

LQTS can be inherited or acquired. The congenital forms are caused either by autosomal dominant or less often by autosomal recessive genetic mutations, almost all of which encode for abnormal cardiac ion channels (table 1). The acquired forms are caused by a large number of stimuli, most frequently antiarrhythmic and other types of drugs and electrolyte and metabolic abnormalities (table 2). (See "Genetics of congenital and acquired long QT syndrome" and "Acquired long QT syndrome".)

An important distinction between the congenital and acquired forms is that the latter can usually be reversed by correction of the underlying disorder or discontinuation of the offending drug. However, some patients with acquired LQTS have a "forme fruste" of congenital LQTS in which a mutation or polymorphism in one of the LQTS genes is clinically silent until the patient is exposed to a particular drug or other predisposing factor. (See "Acquired long QT syndrome", section on 'Mutations in LQTS genes'.)

The heterogeneity of LQTS makes the diagnosis, therapy, and prognosis of this disorder challenging. Nonetheless, certain guidelines can be made concerning the management of these patients.

The natural history, prognosis, and treatment of congenital LQTS will be reviewed here. Clinical manifestations and criteria for the diagnosis of congenital LQTS and issues related to the management of acquired LQTS are discussed separately. (See "Congenital long QT syndrome: Epidemiology and clinical manifestations" and "Congenital long QT syndrome: Diagnosis".)

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Literature review current through: Nov 2017. | This topic last updated: Sep 28, 2017.
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