If you have long QT syndrome (LQTS), you can have sudden and dangerous arrhythmias (abnormal heart rhythms). Signs and symptoms of LQTS-related arrhythmias often first occur during childhood and include:
Often, people who have LQTS 3 develop an abnormal heart rhythm during sleep. This may cause noisy gasping while sleeping.
Sometimes long QT syndrome doesn't cause any signs or symptoms. This is called silent LQTS. For this reason, doctors often advise family members of people who have LQTS to be tested for the disorder, even if they have no symptoms.
Medical and genetic tests may reveal whether these family members have LQTS and what type of the condition they have.
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