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Diagnosis of congenital long QT syndrome

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

INTRODUCTION

The long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram (ECG) (waveform 1) that can lead to symptomatic ventricular arrhythmias and can lead to an increased risk of sudden cardiac death [1-3]. This syndrome is associated with an increased risk of a characteristic life-threatening cardiac arrhythmia, known as torsades de pointes or "twisting of the points" (waveform 2) [4,5]. The primary symptoms in patients with LQTS include palpitations, syncope, seizures, and cardiac arrest.

The long QT syndrome may be congenital or acquired [6-9]. Mutations in at least 13 genes have been identified thus far in patients with genetic LQTS; the distinct genetic types are designated LQT 1 through 13 (table 1). (See "Genetics of congenital and acquired long QT syndrome".)

Two clinical phenotypes have been described in congenital LQTS that vary with the type of inheritance and the presence or absence of sensorineural hearing loss [9]:

The more common autosomal dominant form, the Romano-Ward syndrome, has a purely cardiac phenotype.

The autosomal recessive form (or compound heterozygous), the Jervell and Lange-Nielsen (JLN) syndrome, is associated with LQTS and sensorineural deafness. (See "Clinical features of congenital long QT syndrome", section on 'Congenital sensorineural deafness'.)

                          

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Literature review current through: Nov 2016. | This topic last updated: Thu May 01 00:00:00 GMT+00:00 2014.
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