What causes long QT syndrome?
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Dr. William D. Knopf of Piedmont Heart Institute answered:The following are the causes for long QT syndrome:
Inherited Long QT Syndrome
Faulty genes cause inherited long QT syndrome (LQTS). These genes control the production of certain types of ion channels in your heart. The genes may cause the body to make too few ion channels or ion channels that don't work properly, or both.
If you have inherited LQTS, you received the faulty gene(s) from one or both of your parents.Inherited LQTS is a lifelong condition.
There are seven known types of inherited LQTS (types 1 though 7). The most common types of inherited LQTS are types 1, 2, and 3. Some types of LQTS stem from either faulty or lacking potassium ion or sodium ion channels.
If you have LQTS 1 or LQTS 2, the flow of potassium ions through the ion channels in your heart cells isn't normal. This may cause problems when you exercise or when you're surprised or experience emotional stress.
During these situations, you may develop a rapid and uncontrollable heart rhythm that prevents your heart from pumping blood. This will result in death if it's not quickly brought under control.
If you have LQTS 3, the flow of sodium ions through ion channels in your heart cells isn't normal. This can trigger a rapid and uncontrollable heart rhythm that can be fatal. In LQTS 3, problems usually occur when your heart beats slower than normal, such as during sleep.
Acquired Long QT Syndrome
Certain medicines or other medical conditions can cause acquired, or noninherited, LQTS.
Medication-Induced Long QT Syndrome
Presently, more than 50 medicines have been recognized to cause LQTS. Some of the commonly used medicines that may cause LQTS include:
- Antihistamines and decongestants
- Diuretics (pills that remove excess water from your body)
- Antibiotics
- Antidepressants
- Cholesterol-lowering medicines and some diabetes medicines
This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.
The following are the causes for long QT syndrome: Inherited Long QT Syndrome Faulty genes cause inherited long QT syndrome (LQTS). These genes control the production of certain types of ion channels in your heart. The genes may cause the body to... More -
The Long QT Syndrome is commonly inherited. There are at least two inherited variants, and in one type, individuals with Long QT Syndrome are deaf. The majority of people with Long QT Syndrome have family members with the disorder and have had at least one episode of fainting by age 10. Even if the disorder has not been diagnosed in the family (as relatives may have died of sudden unknown causes), any history of fainting or sudden loss of consciousness during exercise or strong emotion necessitates medical tests.
The Long QT Syndrome is commonly inherited. There are at least two inherited variants, and in one type, individuals with Long QT Syndrome are deaf. The majority of people with Long QT Syndrome have family members with the disorder and have had at... More
