What is Long QT Syndrome?

Long QT Syndrome is a pathological cardiac condition which involves fast irregular rhythms. In Long QT Syndrome, the heartbeat becomes so fast that it may cause the person to become unconscious or may even cause a seizure. In some cases it may also prove to be fatal for the individual. Long QT Syndrome is also genetically linked and certain gene mutations may put an individual at risk for this condition. Long QT Syndrome is a treatable medical condition where the affected individual needs to limit physical exertion and avoid certain classes of medications which are known to cause Long QT Syndrome. In some cases people with Long QT Syndrome may need external devices in order to control the heart rhythm.

What is Long QT Syndrome?

What Causes Long QT Syndrome?

Under normal circumstances the heart contracts and relaxes in order to pump blood throughout the body. This contraction and relaxation is carried out by a series of electrical impulses which are generated at the SA node which is located at the top of the atrium. After each heartbeat, these impulses need to recharge before the next heartbeat. In Long QT Syndrome, the process of recharging takes more time than normal by the heart muscles resulting in symptoms. Studies suggest that there are at least 12 types of genes which are responsible for causing Long QT Syndrome and are responsible for about 80% of cases of Long QT Syndrome. Studies also suggest that there are two types of Long QT Syndrome inherited and acquired.

There are two types of inherited Long QT Syndrome:

Romano-Ward Syndrome: This type of Long QT Syndrome is caused when the offending gene is inherited from one parent and is quite common form of the condition.

Jervell and Lange-Nielsen Syndrome: This type of Long QT Syndrome is much rare and is caused when the offending gene is inherited from both parents. It is usually found in children who are born deaf.

Acquired Long-QT Syndrome: This form of disease is normally caused due to certain types of medications like antibiotics, antidepressants, antipsychotics, diuretics, and certain classes of cardiac medications.

What are the Risk Factors for Long QT Syndrome?

Below mentioned are some of the risk factors for Long QT Syndrome:

  • If any child or an adolescent is suffering from unexplained fainting episodes or seizures for which the exact etiology is unclear then such children might be suffering from a Long QT Syndrome.
  • The above holds true even for the family members of the children and first-degree relatives of people with a history of Long QT syndrome.
  • If an individual takes medications which is known to cause Long QT Syndrome puts the individual at risk for this condition.
  • Individuals who have a depleted potassium or magnesium levels are also at risk for developing Long QT Syndrome.

What are the Symptoms of Long QT Syndrome?

Long QT syndrome generally is asymptomatic and can be diagnosed only when an individual undergoes an ECG. This may be performed to rule out some other condition and Long QT Syndrome may be diagnosed incidentally. Some of the classic features of a Long QT Syndrome are:

  • Unexplained fainting or syncopal episodes especially when in high emotional state
  • Unexplained seizures
  • Incidences of sudden death.

How is Long QT Syndrome Diagnosed?

In case if an individual is suspected of having a Long QT Syndrome then the following tests may be performed to confirm the diagnosis:

Electrocardiogram: This test shows the heartbeat in the form of electrical impulses. This test can show whether there is any abnormality in the rhythm of the heart and whether the heart is functioning normally.

Holter Monitor: A Holter monitor is a small portable device which is attached to the patient and the heart rhythms are monitored. This device may be put in for 24 or 72 hours. This is quite an effective way of diagnosing any abnormality in the rate and rhythm of the heart.

Event Recording: This test is quite similar to Holter Monitor except that the individual has to wear a portable ECG recorder to keep a track of the rhythm of the heart.

Non-exercise Stress Test: In this method a medication is given to the patient that stimulates the heart muscles as when a person does some exercise and then an ECG is taken to look for any abnormal rhythms.

Electroencephalogram: This is done in cases where the patient has experienced a seizure without any prior history of epilepsy. In this test, the electrical activity of the brain is measured looking for any abnormality in that part.

Genetic Testing: Since there is a genetic link to Long QT Syndrome hence a genetic link is also very helpful especially if there is a family history of this disorder to look for any genetic defect which can lead to development of this condition.

How is Long QT Syndrome Treated?

If Long QT Syndrome is inherited, then the physician may prescribe certain medications or may implant certain devices to control the rhythm of the heart. The physician will also recommend certain lifestyle changes to control abnormal heart rhythms. Some of the medications used for treatment of Long QT Syndrome are beta blockers like Inderal or Corgard which slow down the heart rate and lessen the chances of a Long QT Syndrome. Some of the other medications are mexiletine, potassium, or fish oil.

If medications are not effective in controlling the rhythm of the heart then the physician may prescribe certain devices which will be implanted to control the heart rate and rhythm. Some of these devices are a pacemaker which is implanted in the chest with the leads connected to the heart which controls the heart rate whenever it becomes abnormal. Another such device is an ICD or Implantable Cardioverter-Defibrillator.

A procedure called as Left Cardiac Sympathetic Denervation Surgery can also be performed for Long QT Syndrome. This surgery deals in surgically removing some nerves which are responsible for controlling the heart rhythm which markedly reduces the risk of fatal complications of Long QT Syndrome. This procedure is performed usually in people who are at higher risk for potential fatal complications of Long QT Syndrome.

Do's and Don'ts When Having Long QT Syndrome

Some of the measures which can be taken by an individual with Long QT Syndrome are:

  • Avoid overexertion
  • Do not indulge in exceedingly strenuous activities at work or at home
  • Keep an eye for the symptoms and go to the physician immediately if you experience even the slightest of discomfort
  • Make sure that your fellow workers, teachers, and family and friends are aware of your condition so that help may be available whenever required.

What are the Complications of Long QT Syndrome?

Usually Prolonged or Long QT Syndrome does not pose an immediate threat; however, if it is not controlled appropriately of if the affected individual is under an increased amount of stress then it may cause a few problems to the patient like an uncontrollable heart rhythm resulting in less blood being pumped from the heart affecting other parts of the body resulting in frequent fainting episodes. Long QT Syndrome may also cause a condition called ventricular fibrillation wherein the heart starts to beat exceedingly fast which may cause resultant brain damage if it is not controlled in time. Hence it is best to contact your physician if you suspect that you may have Long QT Syndrome.

Written, Edited or Reviewed By:

, MD, FFARCSI

Last Modified On: May 2, 2016

Pain Assist Inc.

Pramod Kerkar
  Note: Information provided is not a substitute for physician, hospital or any form of medical care. Examination and Investigation is necessary for correct diagnosis.

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