Definition:

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, T.  The interval in which the lower chambers of the heart (ventricles) activate, contract, and inactivate is called the the QT interval.  In this disorder, the time of the QT interval is longer than normal.  Other causes of Long QT syndrome include certain medication, stroke, familial history, or other neurological disorders.

Symptoms:

• During normal activity, usually no symptoms
• Under intense exercise/emotions or startling, you can have abnormal heart rhythms (prolonged QT interval)
• Fainting (syncope) episodes (at least one by the age of 10)
• Deafness (rare)
• Severe cases - can lead to ventricular tachycardia (very fast, irregular heart beat) and cardiac arrest

Diagnosis:

• Electrocardiogram (ECG) - evidence of longer QT interval
• Stress test - ECG during strenuous exercise allows for better resolution of prolonged QT interval
• 24Hr Heart Rhythm monitor (Holter monitor) - QT interval varies between normal and prolonged, so 24hr monitoring should be sufficient to see the prolonged QT interval

Treatment:

• Change in lifestyle - reduce exercise and strenuous activities
• Medications - beta blockers to alleviate symptoms
• Surgery - repair electrical activity of the heart via implantable cardioverter defibrillator (ICD) or an artificial pacemaker