Long Q-T Syndrome (LQTS)

What is the long Q-T syndrome (LQTS)?

The long Q-T syndrome (LQTS) is a form of heart disease. It gets its name from the unusual pattern of the electrocardiogram seen in people with the disease. It sometimes results in life-threatening heart rhythm problems, particularly when there is emotional or physical stress.

How does it occur?

LQTS is often present from birth. It often runs in families. Many gene defects that can cause the syndrome have been identified. These defects affect the ability of the heart's muscle cells to use sodium and potassium properly. As a result, abnormal heart rhythms occur off and on. Some of these rhythms may be very rapid and cause symptoms. LQTS can appear at any age, but most often occurs in children and young adults.

What are the symptoms?

The most common symptom is fainting caused by stress. The stress may be physical, emotional, or even playful tickling. Fainting spells are usually brief, but injuries can occur from falling. Sometimes people have both fainting spells and seizures. The most serious symptom is sudden loss of consciousness followed by death.

Some people with LQTS have few or no symptoms. Even so, they are still at an increased risk of life-threatening heart rhythms.

How is it diagnosed?

Your healthcare provider will ask about your medical history, including your symptoms. Your provider also needs to know if you have family members who have unexplained fainting spells. If the faints occur during emotional or physical stress, LQTS is a likely possibility. Because it runs in families, other family members should also be tested.

You will have an electrocardiogram (ECG) to measure the electrical activity of your heart. If a certain pattern shows on your ECG, you may be diagnosed with LQTS.

How is it treated?

The heart rhythms of people with LQTS are very sensitive to adrenalinelike chemicals produced by their own bodies. Blocking these chemicals helps relieve symptoms. Beta blockers are very effective in reducing heart rhythm problems in LQTS.

Most people also benefit from treatment with a pacemaker to slightly speed up the heart rate.

Some people may need an implantable cardiac defibrillator (ICD). An ICD is a device that monitors the heart and shocks it back into a normal rhythm if a life-threatening heart rhythm is detected.

With treatment, people with LQTS can lead fairly normal lives. Most people with LQTS can be physically active and handle emotional stress without fear of symptoms.

When should I call my healthcare provider?

Your healthcare provider will develop guidelines for your treatment. They will include recommendations about physical activity. If you have LQTS and notice spells of light-headedness or fainting, you should call your healthcare provider promptly. You should also call your healthcare provider if you feel your heart racing for short spells.