Long QT Syndrome (LQTS)

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What Is Long QT Syndrome (LQTS)?

LQTS is a type of arrhythmia that can lead to an abnormally fast heartbeat.

This fast heartbeat can cause:

  • Heart palpitations.
  • Fainting spells.

Long QT syndrome causes

  • Inherited LQTS causes. An altered gene that may have come from a parent.
  • Acquired LQTS causes. Medicine, mineral deficiencies, or other health conditions.

Sometimes, both genetics and other factors combined can lead to LQTS.

LQTS risk factors

Some people are more likely to get the condition than others.

This includes people who:

  • Have a family history of LQTS.
  • Take drugs known to cause LQTS, such as some antibiotics, antifungals, or water pills.
  • Have a disorder that leads to malnutrition.
  • Have a history of unexplained sudden cardiac arrest.

Long QT syndrome complications

LQTS can lead to fainting spells, seizures, or, rarely, sudden cardiac arrest.

The heart rhythm changes from LQTS often correct on their own — but can be deadly when they don't.

Treatment for LQTS helps prevent complications.

Why choose UPMC for LQTS care?

The Center for Inherited Heart Disease at UPMC:

  • Takes a thorough, family-based approach to caring for people with LQTS.
  • Provides a team of heart doctors for both children and adults, genetic counselors, heart surgeons, and others.
  • Helps you get answers about your genetic heart disease.

Long QT Syndrome (LQTS) Symptoms and Diagnosis

Not everyone with LQTS has symptoms.

When they do have symptoms, the most common are:

  • Fainting spells.
  • Seizures.
  • Heart palpitations.

Diagnosing LQTS

If your doctor suspects you have LQTS, they'll ask you about your symptoms, medical history, and family history.

They'll also do a physical exam and may order tests, such as:

  • EKG. This test records your heart's electrical activity.
  • Holter monitor. This test also records your heart's electrical activity, but for longer than an EKG. You wear this device for 24 or 48 hours.
  • Exercise stress test. This test will catch a long QT interval that occurs only during exercise.

Genetic testing for LQTS

Because LQTS is an inherited disorder, your doctor may also suggest genetic testing.

Before the test, a genetic counselor will talk to you about the risks and benefits of DNA testing. They'll also tell you about any limits in translating the results.

If you carry a gene change for LQTS, there's a risk that you may pass it along to your children. Doctors may suggest that your parents, siblings, and children also have the test.

Your care team can talk with family members about their LQTS risks and DNA testing.

Long QT Syndrome (LQTS) Treatment

The goal of treatment for LQTS is to avoid sudden cardiac arrest, fainting spells, and fatal heart rhythms.

Your doctor will plan your treatment based on how severe your LQTS symptoms are and your risk for life-threatening problems.

Your doctor may:

  • Prescribe drugs like beta-blockers to slow your heart rate.
  • Implant a cardioverter defibrillator (ICD). An ICD continuously tracks your heart rate. It can send a shock if needed to keep your heart pumping normally.
  • Ask you to make changes to your diet or exercise routine.

Even with treatment, you may not have a normal QT interval on an EKG.