Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.

Diseases

Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Long QT syndrome

*

* Not a rare disease

See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Overview

What is long QT syndrome?

What are the signs and symptoms of long QT syndrome?

What causes long QT syndrome?

How is long QT syndrome diagnosed?

What is long QT syndrome?

Long QT syndrome is a disorder of the heart’s electrical activity that can cause sudden, uncontrollable, and irregular heartbeats (arrhythmia), which may lead to sudden death. Long QT syndrome can be detected by electrocardiogram (EKG). It can be caused by a variety of different gene mutations (changes). It can also be acquired (noninherited) and may be brought on by certain medicines and other medical conditions.[1]
Last updated: 10/4/2013

What are the signs and symptoms of long QT syndrome?

Signs and symptoms of the arrhythmias experienced by people with long QT syndrome includes unexplained fainting, seizures, drowning or near drowning, and sudden cardiac arrest or death.[1] You can read more about these and other symptoms of long QT syndrome on the National Heart Lung and Blood Institute's Web site by clicking here.
Last updated: 10/4/2013

What causes long QT syndrome?

Acquired long QT syndrome can be caused by certain medicines and medical conditions. Some medications that cause long QT syndrome include antihistamines and decongestants, antibiotics, antidepressants, and cholesterol-lowering medicines. Examples of medical conditions that can cause long QT syndrome include excessive diarrhea or vomiting and certain thyroid disorders.[1]

Inherited forms of long QT syndrome are caused by changes in genes that control the heart muscle’s electrical activity.[1] Inherited long QT syndrome may be isolated (occur alone without other associated symptoms) or be due to a genetic syndrome, such as Romano-Ward syndromeJervell Lang-Nielsen syndrome, Anderson-Tawil syndrome, and Timothy syndrome.[2]
Last updated: 10/4/2013

How is long QT syndrome diagnosed?

Long QT syndrome is diagnosed on the basis of electrocardiographic (EKG) findings, clinical findings such as congenital deafness or unexplained fainting, and family history of long QT syndrome or sudden cardiac death. Genetic testing is often performed in families in whom the diagnosis of long QT syndrome has been made or is suspected on clinical grounds.
Last updated: 10/4/2013

References
  1. Long QT syndrome. National Heart Lung and Blood Institute. 2007; http://www.nhlbi.nih.gov/health/dci/Diseases/qt/qt_all.html. Accessed 12/17/2008.
  2. Sovari AA, Kocheril AG, Assadi R Baas AS, Zareba W, Rosero S. Long QT syndrome. eMedicine. 2010; http://emedicine.medscape.com/article/157826-overview . Accessed 4/15/2011.


See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.