What're the symptoms of the long QT syndrome?
The main symptoms of Long QT syndrome are fainting or loss of consciousness. This happens when the rapidly beating heart is unable to supply the brain with sufficient blood and oxygen. This abnormal rhythm may occur during intense emotional excitement, during physical exertion, or less commonly when the sufferer is at rest. When unconscious it is not
possible to feel the patient’s pulse. Consciousness is usually regained within one or two minutes as the heart rhythm becomes normal again. People with this syndrome may show prolongation of the QT interval during physical exercise, intense emotion (such as fright, anger or pain), or by a startling noise.
In one type of inherited long QT syndrome, the person is also deaf. Studies of otherwise-healthy people with LQTS indicate that they had at least one episode of blacking out (fainting) by the age of 10. The majority also had a family member(s) with a long QT interval. It should be emphasized that people with LQTS don't necessarily have a prolonged QT interval all the time. Thus, when they have an ECG (as during a routine physical examination), the QT interval may be normal.
Some healthy young people may not have a routine ECG, and LQTS may be suspected because of their family history or because of unexplained fainting episodes. In any family where repeated episodes of fainting or a history of sudden death exist, the cause(s), including long QT syndrome, should be investigated.