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Long QT Syndrome (LQTS)

Long QT syndrome (LQTS) is a heart rhythm disorder that can potentially cause fast, out of control heartbeats. The rapid heartbeats can lead to fainting, seizures or in severe cases sudden death.

LQTS is usually inherited, but it can be developed over time from the usage of certain medications. Some people with congenital LQTS never show any symptoms. If you have a family history of this condition, it is important that you tell your doctor as tests might be recommended to check your heart.

LQTS is a treatable condition. Patients that show minor or no symptoms, your cardiologist may recommend you take or avoid certain medications. For patients that have a history of cardiac arrest or symptoms, surgery or an implantable device may be recommended.

Signs & Symptoms

Most people with LQTS don’t show signs or symptoms, but there are a few to be aware of that include:

  • Fainting
  • Seizures
  • Cardiac arrest


LQTS is diagnosed by the following tests:

  • Treadmill stress test
  • Ambulatory monitor

Your doctor will ask you if you have a:

  • Family history of LQTS, unexplained fainting, cardiac arrest or seizures
  • History of fainting, seizures or cardiac arrest