Long QT Syndrome (LQTS): Symptoms, Causes, Diagnosis and Treatment

Long QT syndrome (LQTS) is a rare inborn heart disorder. LQTS causes a sudden uncontrollable heart rhythm called the arrhythmia which is very dangerous. Arrhythmias are a result of strenuous and stressful work. However, these irregular heart rhythms can also develop without reason. 

The name long QT syndrome is after the abnormal pattern that is seen on an electrocardiogram (EKG). 

This test is performed to detect the electrical activity of the heart. The normal QT interval i.e. the time during which the lower chambers of the heart are triggered to contract and then build the potential to contract again. The normal QT interval of the heartbeat is one third of a heartbeat. If the QT interval is longer than normal, then the patient is said to have Long QT syndrome. The other names for Long QT Syndrome are Romano-Ward syndrome and Jervell and Lange-Nielsen syndrome.
On the surface of each heart muscle cell, there are tiny pores called the ion channels. These tiny ion pores close and open to let the charged potassium, sodium and calcium ions to flow in and out of the cell. This in turn is called the electrical activity of the heart. This electrical activity is responsible for the heart cell to contract co-ordinately during each heartbeat. But in case of people having Long QT syndrome (LQTS), the ion channels in the heart will interrupt the timings of the electrical activity. The reason for this is either the presence presence of small number of ion channels, or their improper functioning and thereby results in the fast and abnormal heart rhythm called arrhythmia which poses a serious threat to life. 

Types and causes of Long QT syndrome (LQTS) 

As mentioned earlier, Long QT syndrome (LQTS) is an inborn disorder and will tend to prevail for the rest of your life. There are different types of LQTS. The most common ones are called LQTS 1, LQTS 2, and LQTS 3. 
The LQTS can also be classified as acquired LQTS and inherited LQTS. Let us have a brief discussion on each one of them.

  • Acquired Long QT Syndrome

This type of LQTS can occur due to many factors like medical conditions, excessive intake of medicine, etc. Acquired LQTS usually affects just one person, not multiple family members. Another fact about the Acquired LQTS is that, it is not passed on to the next generation. Exces sive diarrhoea or vomiting causes a major loss of potassium or sodium ions from the bloodstream which may also cause acquired LQTS. This will last until the levels of these ions in the blood come back to normal.

  • Inherited Long QT Syndrome 

This type of LQTS occurs when a defect develops in the genes that are responsible for the able working of the ion channels in the heart. Inherited LQTS is passed on from the previous generations and may affect several members in the family. 

  • Medication-induced LQTS

LQTS can be even caused by the intake of a few medications. According to the sources there are over 50 medications that have been recognized to cause LQTS. 
Some of the commonly used medicines that may cause LQTS include:

  • Cholesterol-lowering medicines and some diabetes medicines 
  • Antihistamines and decongestants
  • Diuretics (pills that remove excess water from your body)
  • Antibiotics
  • Antidepressants 

The symptoms and signs

There are a few symptoms and signs of long QT syndrome. These symptoms often appear during the childhood. They are:

  • Abnormal heartbeat during sleep
  • Sudden cardiac arrest which could lead to death
  • Fainting

Diagnosis  

In order to diagnose Long QT syndrome (LQTS), the doctors consider the genetic test results, EKG results, and medical history. The doctor will thoroughly examine you,and ask whether you have the symptoms like fainting, acute pain in the chest and loud gasping during sleep, and after careful consideration your doctor will confirm LQTS. 

Treatment  

When you are undergoing treatment for LQTS, the main aim of the treatment is to restore normal QT interval. This in turn will prevent the life threatening abnormal heartbeats and fainting. However, the treatment to take care of your LQTS depends on the type and the severity of LQTS you are suffering from. Beta-blockers and sodium channel blocker medication can used to treat LQTS by reducing the symptoms and slowing the heartbeat rate.
Another effective treatment is implantable cardioverter defibrillators (ICDs). This can be used as an effective treatment to treat patients with congenital long-QT syndrome (LQTS). ICDs are commonly used in patients with syncopes despite beta blocker therapy, and in patients who have experienced a cardiac arrest.

Lifestyle changes required

People who have LQTS are advised to make lifestyle changes. This in turn will reduce the risks associated with LQTS. Making lifestyle changes also includes avoiding sports and strenuous exercise. You will also be advised to avoid medicines that trigger the symptoms of LQTS like the medications used to treat depression, blood pressure, cholesterol, etc. 
As a final point, if you have LQTS, then it is very important that you take certain steps to control the symptoms for the rest of your life. See your heart specialist for more guidance.