Long QT syndrome

Long QT syndrome (LQTS) is a disorder of the heart's electrical system that can cause episodes of fast, disordered heartbeats, called arrhythmias. It is named after the pattern seen on an electrocardiogram (ECG or heart tracing).

People with LQTS may experience fast or irregular heartbeats, fainting or seizures. If the heart beats irregularly for a long time it can cause cardiac arrest in some people, and possibly sudden death.

If you have LQTS, you may have been born with a gene that puts you at risk. Some medicines can increase your risk of an abnormal fast heart rhythm if you have this gene. LQTS may also be caused by certain medicines.

If you have any symptoms of LQTS such as fainting, seizures or irregular heartbeats, you should see your doctor, who can advise you on treatment. If you have a family member who has been diagnosed with LQTS, ask your GP if you need a referral to a (heart specialist).

Long QT syndrome can be diagnosed by your doctor by doing a test called an electrocardiogram (ECG). This test measures the heart's electrical activity. An ECG creates a graph of your heart's electrical activity. It's a simple, safe and painless test.

Long QT syndrome is named after the distinctive pattern seen on an ECG.

If someone in your family is diagnosed with LQTS, it is important that other close family members are also checked for the condition .This could involve having an ECG or undergoing genetic testing.

The aim of treatment in LQTS is to prevent heart arrythmias.

Treatment may involve limiting intense physical activity, avoiding certain medicines or taking medicines to help prevent you having fast or irregular heartbeats. Some people with LQTS may also need surgery that places an implantable cardioverter defibrillator (ICD) in the chest. An ICD is a device that monitors your heart rhythm and can treat episodes of arrhythmias if they occur.

Learn more about implantable cardioverter defibrillators (ICDs).

Long QT Syndrome is usually genetic and cannot be prevented. It is usually present from birth but might only be diagnosed during childhood, young adulthood or later in life.

If your doctor has diagnosed you with LQTS, you need to avoid medicines that increase your risk of an abnormal heart rhythm. Tell your doctors you have LQTS before they prescribe a medicine, and check with your pharmacist before you take a new medicine.

If LQTS is not properly controlled, it can lead to serious episodes of arrhythmias, possibly causing cardiac arrest and sometimes even death.

For more information about the causes, symptoms, diagnosis and management of LQTS, see the Sydney Children's Hospital Network website (Opens in new tab).

Call healthdirect helpline on 1800 022 222 at any time to speak to a registered nurse (known as NURSE-ON-CALL in Victoria) for more information and advice.