Long QT syndrome (LQTS) is a disorder of the heart's electrical system that can cause fast, chaotic heartbeats, called arrhythmias. It is named after the distinctive pattern seen on an electrocardiogram (ECG or heart tracing).
If you have long QT syndrome, you may have been born with a gene that puts you at risk. It might also be caused by certain medications.
People with long QT syndrome may experience fast or irregular heartbeats, fainting or seizures. If the heart is beating erratically for a long period it can cause cardiac arrest in some people, and possibly sudden death.
Treatment for long QT syndrome often involves limiting physical activity, avoiding certain medications or taking medications to help prevent the development of fast or irregular heartbeats. Some people with long QT syndrome may also need surgery and an implantable device to control the rhythm of the heart.
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Last reviewed: May 2018