Clinical features of congenital long QT syndrome
- Stephen P Seslar, MD, PhD
Stephen P Seslar, MD, PhD
- Assistant Professor of Cardiology and Pediatrics
- University of Washington
- Peter J Zimetbaum, MD
Peter J Zimetbaum, MD
- Section Editor — Cardiac Arrhythmias
- Professor of Medicine
- Harvard Medical School
- Charles I Berul, MD
Charles I Berul, MD
- Section Editor — Cardiac Arrhythmias
- Professor of Pediatrics
- George Washington University
- Section Editors
- John K Triedman, MD
John K Triedman, MD
- Section Editor — Pediatric Cardiology
- Professor of Pediatrics
- Harvard Medical School
- Samuel Lévy, MD
Samuel Lévy, MD
- Section Editor — Cardiac Arrhythmias
- Professor of Cardiology
- University of Marseille, France
- Samuel Asirvatham, MD
Samuel Asirvatham, MD
- Section Editor — Long QT Syndrome
- Professor of Medicine and Pediatrics
- Mayo Clinic College of Medicine
The long QT syndrome (LQTS) is a disorder of myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram (ECG) (waveform 1) and an increased risk of sudden cardiac death [1-3]. This syndrome is associated with an increased risk of a characteristic life-threatening polymorphic ventricular tachycardia known as torsades de pointes or "twisting of the points" (waveform 2A-B) [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. While mutations in numerous genes have been identified in patients with congenital LQTS (table 1), 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.)
The epidemiology, clinical features, and conditions that are associated with congenital LQTS will be reviewed here. The diagnosis and management of congenital LQTS in children and adults and the clinical features of acquired LQTS are discussed separately. (See "Diagnosis of congenital long QT syndrome" and "Prognosis and management of congenital long QT syndrome" and "Acquired long QT syndrome".)
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- CLINICAL MANIFESTATIONS
- TYPES OF ARRHYTHMIAS
- Polymorphic VT/torsades de pointes
- AV block
- Atrial arrhythmias
- TRIGGERS OF ARRHYTHMIA
- External triggers
- Pause dependence
- Influence of genotype on triggers
- Medications and electrolyte abnormalities
- ASSOCIATED CONDITIONS
- Congenital sensorineural deafness
- - Recommendations for screening ECG in congenital sensorineural deafness
- Sudden infant death syndrome
- - Recommendations for ECG screening in infants
- Andersen syndrome
- Turner syndrome
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS