Long QT syndrome 

Some people with LQTS have no symptoms and the condition is only detected on a heart monitor or during an electrocardiogram (ECG) carried out for other reasons. Some symptoms include:

• fainting or blackouts
• palpitations or chest fluttering
• feeling lightheaded
• cardiac arrest

These symptoms can be triggered by strenuous exercise, stress, a sudden noise or a slow heart rate while sleeping.

An electrocardiogram (ECG) is the main way to detect long QT syndrome. If you have this condition, it shows up on an ECG as a lengthened QT interval, which is part of the heartbeat cycle.

• Sometimes other tests are needed such as an exercise ECG, which is an ECG carried out during physical exertion. Alternatively, you may be given a Holter monitor, which is a portable ECG recording device to wear for up to a few days to get more readings. Genetic testing can also be carried out and may help determine your type of LQTS.

Treatment can help prevent the symptoms of LQTS and minimise the risk of fainting or cardiac arrest. Inherited LQTS is usually treated with medicines. Depending on your symptoms, you may also need to have an implantable cardioverter defribillator device fitted. This is implanted under the skin on your chest and wires connect it to your heart. It monitors your heart rhythm and can give a brief electrical shock to reset the rhythm. People with non-inherited LQTS are usually treated by changing the medicines that caused the problem.