Long QT Syndrome (LQTS)

What is Long QT Syndrome?

Long QT syndrome (LQTS) is a rhythm disorder of the heart’s electrical system, which can cause a person to have fainting spells and fast or irregular heartbeats. In some cases, these erratic heartbeats can trigger a seizure or even cause sudden death.

LQTS can be caused by some medications, like certain anti-psychotics, antihistamines, and ironically, some antiarrhythmics. A family history of LQTS, mutations in the genes KCNQ1 and SCN5A, and certain conditions, like Jervell and Lange-Nielsen syndrome, can also cause long QT syndrome. In predisposed individuals, stress or vigorous activity can set off the symptoms of LQTS; for instance, if an athlete has undiagnosed LQTS, he or she could suffer from sudden cardiac death during a sporting event.

What are the Symptoms of Long QT Syndrome?

LQTS can sometimes present itself as silent LQTS, meaning there are no discernible symptoms. Even if a person doesn’t have symptoms, it is better to be tested for the disorder anyway if he or she has a family history of the condition.

If a person does have symptoms, they often first appear during childhood. These symptoms include, fluttering feelings in the chest, near drowning incidents while swimming, unexplained fainting, and sudden cardiac arrest. Some people have arrhythmia at night, and they may make loud gasping sounds while they sleep.

How is Long QT Syndrome Treated?

There are many treatments for LQTS. For instance, a doctor can identify which medications a patient should or shouldn’t be on. Typically beta-blocking or sodium-channel blocking medications are used since they can prevent the heart from beating too quickly during emotional or physical stressors.

Certain lifestyle changes can also lessen the symptoms of LQTS. For instance, a doctor may recommend adding more potassium-rich foods or taking supplements. A person may need to avoid triggering physical or emotional activities.

In more serious cases, an implantable cardioverter defibrillator (ICD) or pacemaker may be needed. Surgery to correct the heart’s rhythms may be needed if a person is at high risk for sudden death.

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Last Reviewed:
October 06, 2016
Last Updated:
September 01, 2017