Congenital long QT syndrome: Epidemiology and clinical manifestations
- Peter J Schwartz, MD
Peter J Schwartz, MD
- Professor of Cardiology and Director of the Center for Cardiac Arrhythmias of Genetic Origin
- IRCCS Istituto Auxologico Italiano
- Michael J Ackerman, MD, PhD
Michael J Ackerman, MD, PhD
- Windland Smith Rice Cardiovascular Genomics Research Professor
- Professor of Medicine, Pediatrics, and Pharmacology
- Director of Genetic Heart Rhythm Clinic and the Windland Smith Rice Sudden Death Genomics Laboratory
- Mayo Clinic College of Medicine and Science
- Section Editors
- John K Triedman, MD
John K Triedman, MD
- Section Editor — Pediatric Cardiology
- Professor of Pediatrics
- Harvard Medical School
- Samuel Asirvatham, MD
Samuel Asirvatham, MD
- Section Editor — Long QT Syndrome
- Professor of Medicine and Pediatrics
- Mayo Clinic College of Medicine
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 an increased risk of sudden cardiac death [1,2]. The primary symptoms in patients with LQTS include syncope, seizures, and cardiac arrest. 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 2A-B) [3,4].
LQTS may be congenital or acquired [1,5]. Mutations in at least 17 genes have been identified thus far in patients with congenital LQTS (table 1) . Acquired LQTS usually results from undesired QT prolongation and potential for QT-triggered arrhythmias by either QT-prolonging disease states, QT-prolonging medications (www.crediblemeds.org), or QT-prolonging electrolyte disturbances (table 2) . (See "Genetics of congenital and acquired long QT syndrome".)
While mutations in numerous genes have been identified in patients with congenital LQTS, two clinical phenotypes have been described that differ in the type of inheritance and the presence or absence of sensorineural hearing loss:
●The more common autosomal dominant form, the Romano-Ward syndrome, has a purely cardiac phenotype. (See "Genetics of congenital and acquired long QT syndrome".)
●The autosomal recessive form, the Jervell and Lange-Nielsen syndrome, is associated with LQTS and sensorineural deafness, and a more malignant clinical course . (See 'Congenital sensorineural deafness' below.)To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information on subscription options, click below on the option that best describes you:
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- CLINICAL MANIFESTATIONS
- Patient characteristics
- - Age at diagnosis
- - Frequency of symptoms
- - Types of arrhythmias
- Polymorphic VT/torsades de pointes
- AV block
- Atrial arrhythmias
- - Triggers of arrhythmia
- Pause dependence
- External triggers
- Influence of genotype on triggers
- Medications and electrolyte abnormalities
- ASSOCIATED CONDITIONS
- Congenital sensorineural deafness
- Sudden infant death syndrome
- Andersen syndrome
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS