Jervell and Lange-Nielsen
What causes long QT syndrome?
To understand the underlying cause of long QT syndrome, it's important to know how the heart cells work.
On the surface of each heart muscle cell are tiny pores, or ion channels. These open and close to let electrically charged sodium, calcium and potassium atoms (ions) flow into and out of the cells.
This passage of ions generates the heart's electrical activity. The electrical signal spreads from the top of the heart to the bottom, causing the heart to contract and pump blood.
In most cases of long QT syndrome, the flow of potassium ions out of the heart muscle's cells is delayed. This means that after each heartbeat, your heart can take longer to reset itself.
Inherited long QT syndrome
Long QT syndrome is often inherited from a parentas afaulty gene.The abnormal gene affects the proteins that make up the ion channels in the heart cells. The ion channels may not work well, or there may not be enough of them, which disrupts the heart's electrical activity.
Drug-induced long QT syndrome
Certain commonly used medicines can also trigger long QT syndrome, including some types of:
- antibiotics
- antihistamines
- antidepressants
- antipsychotics
- diuretics
- heart medications
Cardiac Risk in the Young has published a list of medications that people with long QT syndrome should avoid .
Drug-induced long QT syndrome usually happens in people with an inherited higher risk of developing it, such as those with slight genetic heart defects.
For more information, you can read the Sudden Arrhythmic Death Sydrome's (SADS UK) guide about acquired, drug-induced long QT syndrome (PDF, 158kb) .
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Long QT syndrome causes problems with the electrical activity of the heart. It's uncommon, occurring in around 1 in every 2,000 people.
Symptoms of long QT syndrome
There are usually no physical signs of long QT syndrome, and some people don't experience any symptoms. The most common symptoms are blackouts or seizures caused by the interruptions to the heart's r
What causes long QT syndrome?
To understand the underlying cause of long QT syndrome, it's important to know how the heart cells work. On the surface of each heart muscle cell are tiny pores, or ion channels. These open and close
What does 'long QT' mean?
Every time your heart beats, it produces tiny electrical signals. An electrocardiogram (ECG) machine traces these signals on paper a typical pattern is shown below. As the graphshows, each heart
Diagnosing long QT syndrome
Ifyour GPthinks you havelong QT syndrome after assessing your symptoms, they may recommend that you have an ECG and refer you to a heart specialist (cardiologist). In particular, if blackouts have oc
Treating long QT syndrome
Most people with inherited long QT syndrome will need treatment with medicines. Beta-blockers , such aspropranololornadolol, may be prescribed to help control irregular heartbeats and slow down your
Living with long QT syndrome
With appropriate treatment, such as medication or surgery, it should be possible to lead a relatively normal lifestyle. However, you may need to make some lifestyle adjustments to reduce your risk of
Information about you
If you have long QT syndrome, your clinical team may pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS). This helps scientists look for
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