Long QT Syndrome: A Silent Killer
Stories of athletes who collapse and die grab the headlines, but you may not hear about the other 4,000 or so American children and young adults who die each year when their hearts malfunction because of "long QT syndrome." It's a silent disorder of the heart's electrical system that causes an irregular heartbeat, loss of consciousness, and sometimes death.
The good news: If long QT syndrome is diagnosed, death is preventable with medicine or in some cases a pacemaker or automatic defibrillator. Dr. Michael Ackerman joined the Early Show from the Mayo Clinic in Rochester, Minnesota, to explain what long QT syndrome is and how parents can recognize and, if necessary, treat it.
First, can you define long QT?
It's an electrical abnormality in the heart. The heart works as a pump. It needs electrical signals to fire. The problems with long QT occur when the heart is recharging itself. Hearts with long QT take longer to recharge and it's that charge or discharge that tells the heart to squeeze. For most people this will go unnoticed and they live just fine, but sometimes this delay can cause what we call an electrical 'hiccup.' It causes the heart to start spinning out of control. And it's the length of time of that episode that determines what a person will suffer. It could be a fainting spell or last longer and result in a seizure; or it could cause sudden death.
What triggers these electrical hiccups?
All the triggers seem to be linked to our 'fight, flight or fright' response. We know that competitive sports or intense exercise can be a trigger. Swimming is also a trigger. We're not sure why. It could be the cold water on the face or way we hold our breath when we swim, but it is a trigger. Another is auditory--loud noises. Also, emotional stress, certain medications, and sometimes, if you have a particular kind of long QT, sleep can be a trigger.
Symptoms are vague and sometimes not present. What should we look out for?
The most common symptom is fainting or sudden loss of consciousness. More severe would be a seizure. But sometimes the first symptom is sudden death. What parents need to do is pay attention to fainting spells. Fainting is very common: 10-15% of all kids faint. Only one in 5,000 has long QT. But parents should be aware of what I call unusual fainting--fainting that just doesn't sound right, like when a child is swimming laps or fainting at a track meet when the starter's gun goes off. Parents need to distinguish between good and bad fainting.
What about family history?
Check the family history. It's a great way to understand why your child could have long QT. Sometimes a relative will die an unexplained death while swimming or a perfectly healthy relative may have had an car accident that couldn't be explained. Or maybe an aunt or uncle will faint after an argument. These kinds of things are all potential clues.
This is a diagnosis tha can be really tough on kids. How much do they have to change their lifestyle?It can be devastating. Basically, they're benched. They really shouldn't be participating in sports or activities that can cause too much exertion on the heart.
The good news is that death can be prevented with treatment. What's the most effective course of treatment?
The main treatment is medicine called beta blockers. It is the best way to blunt the triggers associated with the fight, flight, and fright response. They prevent people from feeling that arousal. If we had further concerns we could use a device-therapy like a pacemaker or an automatic defibrillator. The defibrillator is great. It's what Vice President Cheney just received. It can jumpstart a heart that's spinning out of control. Treatment can also be the avoidance of drugs that can trigger long QT.
What is the best way to diagnose?
After taking a family history, the best method is the electrocardioram (ECG). A doctor may not see the long intervals associated with long QT, but they can be detected if you do a stress test and take an ECG. Genetic testing is still a few years off. Right now we've identified five known genes, but that's only 60% of the genes that could cause this disorder. There's no clinical test available yet.
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