Long QT Syndrome (LQTS) is a disorder of the heart rhythm that can potentially cause a fast and chaotic heartbeat. These fast heartbeats can cause you to faint suddenly. Some people with this disease have seizures. In some severe cases, LQTS can cause sudden death.
Some people are born with a genetic mutation that causes long QT syndrome (congenital long QT syndrome). Long QT syndrome can be caused by certain drugs, mineral imbalances, or medical conditions (acquired long QT syndrome).
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- Many people with long-standing QT syndrome have no signs or symptoms. You may only be aware of your condition because:
- Results of an electrocardiogram (EKG) done for an unrelated reason
- A family history of long QT syndrome
- Genetic test results
- Chambers and heart valves
- Ventricles and Heart Valves Open the popup dialog
- Long QT syndrome is a heart rhythm disorder caused by abnormalities in the heart’s electrical charging system. The structure of the heart is normal.
- Typically, the heart sends blood to the body with every heartbeat. The chambers of the heart contract and relax to pump blood. This coordinated action is controlled by your heart’s electrical system. Electrical signals (impulses) travel from top to bottom and cause the heart to contract and beat. After each heartbeat, the system is charged to prepare for the next heartbeat.
- Long QT syndrome takes longer than normal for your heart’s electrical system to recharge between beats. This delay, often seen on an electrocardiogram (EKG), is called the prolonged QT interval.
- Long QT syndrome is often divided into two main categories depending on the cause.
- If you were born with the disease, it is known as congenital long QT syndrome. Some forms of long QT syndrome are the result of a genetic mutation that is passed down through families (hereditary).
The following may increase your risk of developing congenital or acquired long QT syndrome or its symptoms:
- A story about cardiac arrest
- Have a first degree relative (parent, sibling) with long QT syndrome
- Use of drugs known to cause longer QT intervals
- Being a woman and taking heart medication
- Excessive vomiting or diarrhea
- Eating disorders, such as anorexia nervosa, that lead to electrolyte imbalances
Appropriate medical treatment and lifestyle changes can help prevent complications from prolonged QT syndrome.
Complications of long QT syndrome are:
Torsades de pointes (“Torsion des pointes”). It is a life-threatening form of ventricular arrhythmia. The two lower chambers (ventricles) of your heart beat quickly and chaotically, giving the waves on an EKG monitor a twisted look. The heart pumps less blood. Lack of blood in the brain causes you to pass out suddenly, often without warning.
If the episode lasts long, fainting can be followed by a full body attack. If the dangerous rhythm doesn’t correct itself, a life-threatening arrhythmia known as ventricular fibrillation ensues.
Congenital long QT syndrome is caused by a genetic mutation. There is no known prevention. However, with proper treatment, you can avoid dangerous heartbeats that can lead to complications from long QT syndrome.
You may be able to prevent the health problems that lead to certain types of acquired long QT syndrome through regular checkups and good communication with your doctor. It is especially important to avoid drugs that can affect your heart rate and make the QT interval longer.