Long QT syndrome

Long QT syndrome (LQTS) is a rare heart condition that's usually inherited. It can cause serious problems with your heart rhythm, but there are things you can do to reduce the risk.

Symptoms of long QT syndrome

Long QT syndrome can cause heart palpitations, where you suddenly feel your heart beating irregularly or faster than usual.

Your heart rhythm usually goes back to normal on its own, but if it continues you may have:

• fainting
• a seizure or fit
• a cardiac arrest (where your heart beats so fast that not enough blood gets to your brain, so you become unconscious and stop breathing)

Symptoms can be triggered by exercise, a shock or sudden noise, excitement or stress. They can also happen while you're resting or sleeping.

Many people with long QT syndrome do not have any symptoms. Sometimes it's found when you have a heart rhythm test called an electrocardiogram (ECG) for another reason.

Call 112 if:

• someone's not breathing normally and not moving or responding – they could be having a cardiac arrest
• someone's having a seizure or fit
• someone's fainted and cannot be woken up within 1 minute

Follow the instructions from the 112 operator until an ambulance arrives.

Tests for long QT syndrome

If a GP thinks you could have long QT syndrome, they'll refer you to a heart specialist (cardiologist) for tests and treatment.

Long QT syndrome is diagnosed using an electrocardiogram (ECG), where sensors are put on your chest to check your heart.

You may also need to:

• wear a heart monitor for 24 hours
• have an ECG while exercising

If you have long QT syndrome, the ECG results will show a pattern in the way your heart beats called a "prolonged QT interval".

As long QT syndrome is usually inherited, you may also be offered genetic testing to see if you have genes linked to the condition.

Important

If you're diagnosed with long QT syndrome, your immediate family should also be offered testing, as there's a chance they could also have the condition.

Treatments for long QT syndrome

Treatment for long QT syndrome depends on the cause, your test results, your symptoms and if you're at high risk of serious problems.

You may be offered:

• medicines called beta blockers to help control your heart rhythm – recommended for most people with long QT syndrome
• a small device called an implantable cardioverter defibrillator (ICD) that's put under the skin in your chest, in a similar way to a pacemaker – recommended if you're at high risk of serious heart problems
• surgery to cut certain nerves that affect the heart – only recommended in rare cases if other treatments are not suitable

You'll also be given advice about lifestyle changes to make, and you'll be monitored regularly to check the health of your heart.

Sometimes long QT syndrome is caused by another health condition or medicine. In these cases, treating the condition or stopping the medicine can improve the symptoms.

How to reduce the risk of heart rhythm problems if you have long QT syndrome

If you have long QT syndrome, it's important to avoid triggers that can cause problems with your heart rhythm.

Your care team will give you advice about which lifestyle changes are right for you.