Long QT Syndrome

When your heart’s timing is off, dangerous heart rhythms can happen.

Long QT Syndrome (LQTS) describes a group of disorders that affect the heart’s electrical recharging system. These can result in rapid heartbeats that may trigger fainting or even heart arrest. The QT interval represents the time it takes for your heart to contract and then refill with blood before beginning the next contraction. It lasts just a fraction of second. In people with LQTS, there is a delay in the time it takes for the electrical system to recharge because the heart muscle cells are having trouble recovering from the last contraction. In extreme cases, a long period of these types of abnormal heart rhythms (arrhythmias) can cause sudden death.

LQTS is often a congenital condition that frequently goes undiagnosed or is misdiagnosed as a seizure disorder.

Relatives of family members with LQTS, and children or young adults with unexplained fainting episodes, are at higher risk for LQTS. In addition, medications known to prolong QT intervals, and low calcium levels (often caused by eating disorders) can cause LQTS. Electrocardiograms (EKG), exercise stress tests, ambulatory monitoring and genetic tests may be used to confirm a LQTS diagnosis. Treatment may include a combination of medications (often beta-blockers) and lifestyle changes.

Symptoms may include:
• Syncope (fainting)
• Seizures
• Sudden death
• No symptoms

In some conditions symptoms may occur during:

• Exercise (or within a few minutes after)
• Emotional excitement, especially being startled
• During sleep or upon waking suddenly

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