Long QT Syndrome

Angina is chest pain caused by reduced blood flow to your heart muscle. It is a symptom of coronary artery disease (CAD), which occurs when the arteries supplying blood to the heart become blocked or narrowed.

Overview and Symptoms

Overview and Symptoms

The most common symptom of long QT syndrome is fainting, which can happen without warning. Seizures may also occur if the brain is deprived of oxygen as your heart continues to beat erratically. However, you may not show any signs or symptoms of long QT syndrome.

An electrocardiogram (ECG or EKG) can be performed to check your heart’s electrical signal, and measure whether your heart muscle is taking longer than normal to recharge between beats, which signals LQTS. Other tests may include:

  • Holter monitor, to record your heartbeat
  • Event monitor, to record your heart’s electrical activity
  • Medication stress test
  • Electroencephalogram (EEG)
  • Genetic screening

Long QT syndrome usually affects children or young adults. Most people experience their first episode before the age of 40. In most cases, Long QT syndrome is hereditary, caused by a genetic abnormality. Long QT syndrome can also be caused by a congenital heart defect or by a number of common medications, including:

  • Antihistamines
  • Decongestants
  • Diuretics
  • Antibiotics
  • Antidepressants
  • Cholesterol drugs
  • Some diabetes medications


If you have mild or infrequent symptoms, your doctor may urge you to make certain lifestyle changes, such as avoiding strenuous exercise and managing stress.

Medication can also be prescribed to treat LQTS, including beta-blockers to slow the heart rate, and/or potassium pills to help the heart’s ability to recharge.

If you have more frequent symptoms of LQTS, an artificial pacemaker can be temporarily or permanently implanted under your skin, in the wall of your chest, with electrodes threaded through your veins and into your heart. A pacemaker sends electrical impulses through the electrodes to regulate your heartbeat. It is the most common treatment for arrhythmias that causes symptoms such as fainting.

Surgery to cut the nerves that make the heart beat faster in response to physical or emotional stress may be an option for patients at high risk of death from LQTS.