Long QTSyndrome


Long QT syndrome, or LQTS, is an abnormality in the rhythm of your heartbeat. It causes fast, erratic and sometimes dangerous heartbeats, usually when you exercise or feel stressed. The term “long QT” comes from the pattern doctors see on an electrocardiogram, or EKG, when you have the condition.

Half of all people who have LQTS have their first abnormal heart rhythm by the time they’re 12 years old. About 90 percent have an abnormal heart rhythm by age 40. For this reason, doctors advise family members of people who have LQTS to be tested for this disorder.

Occasionally, people acquire LQTS, meaning they develop it during their lifetime. Some medications – such as antibiotics, diuretics, and antihistamines – and other health conditions can cause acquired LQTS. 

Health conditions that can cause acquired LQTS include severe diarrhea or vomiting, eating disorders such as anorexia nervosa and bulimia, and some thyroid disorders. These conditions lower the sodium or potassium levels in your blood, which can trigger long QT symptoms.

Most people, however, inherit LQTS.


Typically long QT syndrome symptoms first appear in childhood and include:

  • Abnormal heart rhythm during sleep. Unexplained fainting, which can occur when the heart isn’t pumping enough blood to the brain
  • Palpitations, which feel like fluttering in the chest
  • Seizures
The most dangerous side effect of LQTS is sudden cardiac arrest, which happens when your heart suddenly stops beating.

Some people with inherited LQTS never have symptoms.


To diagnose long QT syndrome, your doctor will ask about any symptoms and your family history, and will perform a physical exam. He or she may also refer you to a cardiologist or an electrophysiologist, a doctor who specializes in diagnosing and treating arrhythmias.

Services & Treatment

If you are diagnosed with long QT syndrome, your doctor may also suggest devices such as a pacemaker or an implantable cardioverter defibrillator (ICD). Or you may need surgery on the nerves that regulate your heartbeat.

If you have LQTS:

  • See your doctor regularly.
  • Make sure your family, friends, roommates and co-workers know you have a condition that can trigger cardiac arrest. Tell them to call 911 if you faint.
  • Keep an automated external defibrillator with you. Make sure those with you know how to use it.
  • Talk with your doctor about counseling or support groups if you’re struggling with anxiety about LQTS.

Why Aurora?

You're at the Heart of Our Care 

Since 1977, Aurora Health Care’s Cardiac Electrophysiology Department has been a nationally recognized leader in diagnosing, managing and treating long QT syndrome.

Aurora Health Care offers coordinated care for preventing, diagnosing and treating heart and vascular disease. World-renowned heart and vascular specialists diagnose and treat all types of cardiovascular conditions and disorders, using the most advanced state-of-the-art tools and technologies available today. 

We have 15 hospitals and 155 clinics throughout eastern Wisconsin and northeastern Illinois so you can find a location that's closest to you. 

What’s all this mean to you? Convenient, coordinated and expert care. 

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