An electrocardiogram, or EKG, is a fairly simple test that uses electrodes placed on the skin to record the heart's electrical activity. They've long been used to help diagnose heart disease in people with chest pain or other symptoms of heart trouble.

But the idea of using EKGs to screen symptom-free people for heart problems is controversial.

That's partly because EKGs are imperfect; they don't detect all heart abnormalities that can cause sudden death, and they can falsely suggest problems where there are none.

It would be great to have a test that clearly catches those silent heart problems, with a low risk of “false-positives."

But the EKG is not that," said Dr. Laurel Leslie of Tufts Medical Center in Boston, the senior researcher on the new study.

Right now, the U.S. Preventive Services Task Force recommends against EKG screening for people at low risk of heart disease.

Children and teenagers are at very low risk of having potentially fatal heart disorders. But whenever a young person dies suddenly of cardiac arrest, it's a shock -- and often widely publicized, especially deaths among young athletes.

There's been this debate about whether ECG screening would be practical and effective in preventing these tragic deaths," said Leslie.

Some countries, including Italy and Israel, already have mandatory EKG screening for young athletes. The U.S. is not one of them

There have also been questions about whether EKG screening could be a good idea in kids being prescribed stimulants for attention-deficit hyperactivity disorder -- though that is not currently recommended.

One of the prime arguments against such screening is that heart disorders that are detectable by EKG are so rare in kids that the risk of false-positives outweighs the potential benefits.

HIGH RISK OF FALSE ALARMS

For the new study, published in the journal Pediatrics, Leslie and her colleagues tried to gauge the potential effectiveness of routinely screening symptom-free kids for three heart disorders: hypertrophic cardiomyopathy, long QT syndrome and Wolff-Parkinson-White syndrome.

The three conditions, while rare, are the most common EKG-detectable causes of sudden cardiac death in kids, said Angie Mae Rodday of Tufts, who also worked on the study.

Using data from 30 studies on the heart conditions, the researchers calculated that EKG screening would have a very low risk of false reassurance -- that is, giving an OK to kids who actually have the heart problems.

But it would carry a high risk of false alarms. Even under the best scenario the researchers considered, 59 percent of kids with a positive EKG screen would, in fact, not have any of the three heart conditions.

That's related to the fact that these are rare disorders," Rodday said.

Based on the studies the researchers reviewed, the three heart conditions together occur at a rate of 188 cases for every 100,000 kids.

Sudden death from heart problems is rarer still. In the U.S., estimates range from less than one to about six such deaths for every 100,000 children and teens.

False alarms from screening tests are always concerning because of what comes after.

In this case, Leslie noted, there's the anxiety that positive results cause parents and kids, and the cost and burden of follow-up testing. Abnormal EKGs would typically be followed by an echocardiogram, a more expensive test that looks at the structure and motion of the heart.

This study is just one step in considering whether routine EKG screening is worthwhile, Rodday said.

There's also logistics -- like who would do all of that screening? Some pediatricians have EKG devices in their offices. “But some of these disorders are pretty hard to interpret," Leslie noted.

That means it may take a pediatric cardiologist to interpret the results. And there are only about 1,500 pediatric cardiologists nationwide.

And then there's cost, Leslie said. “People point out that EKGs are inexpensive," she said, noting that the actual test runs about $10 to $25. But that's a lot when multiplied by millions of kids, and there's also the cost of interpreting those tests -- and then any follow-up that may be needed.

For now, Leslie and Rodday suggested that parents who have concerns talk with their pediatrician. There may be some cases where screening could be considered -- like when there's a family history of sudden cardiac death before the age of 50.

The best bet is to talk to your pediatrician," Rodday said.

SOURCE: bit.ly/wnTweB Pediatrics, online March 5, 2012.

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