Long QT Syndrome

Long QT syndrome is a hereditary disorder that disrupts the normal electrical rhythm of the heart. The electrical signals of the heart are recorded in an electrocardiograph in a recognizable wave pattern with various points that are labeled P, Q, R, S, and T.

The interval in which the lower chambers of the heart (ventricles) activate, contract, and inactivate is called the QT interval. In this disorder, the time of the QT interval is longer than normal.

Causes of long QT syndrome include certain medications, stroke, familial history, or other neurological disorders.

Long QT Syndrome Symptoms

Symptoms of long QT syndrome include:

  • Abnormal heart rhythms (a prolonged QT interval) with intense exercise, emotions, or startling
  • Deafness (rare)
  • During normal activity, usually no symptoms
  • Fainting episodes (at least one by the age of 10)
  • Very fast, irregular heartbeat, or ventricle tachycardia, and cardiac arrest in severe cases

Diagnosis of Long QT Syndrome

Your UT Southwestern Medical Center doctor will use several tests to determine the problem. Common diagnostic tests include:

24-hour heart rhythm monitor (Holter monitor)
24-hour monitoring sufficient to detect prolonged QT intervals
Electrocardiogram (ECG)
Provides evidence of longer QT intervals
Stress test
Includes an ECG administered during strenuous exercise, which provides better resolution of prolonged QT intervals

Long QT Syndrome Treatment Options

Treatments for long QT syndrome include:

Change in lifestyle
Reduce exercise and strenuous activities
Beta-blockers to alleviate symptoms
Repair electrical activity of the heart via implantable cardioverter defibrillator (ICD) or an artificial pacemaker

Request an Appointment

To schedule an appointment with a long QT syndrome expert at UT Southwestern's facilities in Dallas or for more information about our services, request an appointment or call 214-645-8300.