ECGs in Sports: What You Need to Know

A top sports cardiologist weighs in on sudden cardiac death, electrocardiogram tests, and what those little squiggles mean.

Before you win, you've got to train. And before that, you'd better get screened.

Generally, pre-participation screening involves filling out a form that asks you questions about your and your family's medical history (think: that form you fill out every year, checking "no," "no," "no"). For most athletes the screening stops there, and it's on to two-a-days and pre-season training. However, when a physician feels an athlete's history or symptoms should be assessed further, an electrocardiogram (also called an ECG or an EKG) may be performed.

ECGs monitor the heart's electrical signals to determine if any irregularities exist and may help assess cardiovascular health for sports participation. During an ECG, several small sticky patches, called electrodes, are placed on the arms, legs and chest and then attached by cables to a machine that records heart activity onto a long sheet of paper. The test takes about five to 10 minutes.

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While ECG testing isn't part of most pre-participation sports screenings in America, some sports teams do require it before placing athletes on the field.  What's more, some independent and non-profit organizations offer ECG testing in training facilities and high schools. The intention of these programs is to eliminate cases of sudden cardiac death—the leading cause of death among young athletes.

Nevertheless, the use of ECGs as an initial screening tool remains controversial. While proponents say that ECGs can pick up underlying heart problems, critics maintain that across-the-board electrocardiograms are not proven to be effective in identifying at-risk athletes and preventing sudden cardiac death. Furthermore, false positives can lead to unnecessary emotional stress, testing, and even disqualification from sports. Finally, some cardiac abnormalities that put athletes at risk are not seen on an ECG.

It's important to remember that physical inactivity is a killer and that the risk of sudden death during sporting activity is very rare. So, at this time, the American Heart Association advises against administering ECGs to athletes who haven't experience heart-related symptoms or have a family or personal history of heart complications.

If you do undergo an ECG, you may wonder what exactly it's examining: your heart's electrical activity. If you remember from biology class, the heart is composed of two upper and two lower chambers. Every time the heart beats, it goes through a coordinated sequence of events. An electrical impulse fires in the upper chambers, causing them to contract while the lower chambers relax, and blood flows into them. That impulse zips down into the lower chambers, resulting in the upper chambers relaxing while the lower chambers contract, pushing blood to the rest of the body. This happens over and over again—50 to 80 times per minute at rest and upward of 200 times per minute at peak exertion!

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Thus, your ECG results, displayed as a series of bumps and spikes, represent the electrical activity with each phase of the heartbeat. These results show if the heart's rate, rhythm and function are all normal at rest.

However, "normal" is a bit of a misnomer. No two hearts are exactly the same, and athletic training can cause changes in the electrical patterns that make it look different from "normal." Your age, sex, ethnicity, fitness level and sport-specific training can all influence the waveforms displayed on your ECG. For instance, a marathon runner's heart may be very different from a weightlifter's heart—and it shows on an ECG.

Sometimes these changes can look similar to ones that would indicate a major heart abnormality in a non-athlete. That is one reason why it's important that the person reviewing your ECG is experienced in treating athletes.

If you do have an abnormal ECG, you will be referred to a cardiologist (hopefully a sports cardiologist). He or she will review your medical and family history, ask you about symptoms you may be having with training, examine your heart, and, if appropriate, send you for further testing to clarify whether the changes are related to normal athletic adaptation or represent a cardiac abnormality.

In most cases, further testing reveals that the patient's heart is simply a healthy athlete's heart. Occasionally, however, minor heart problems are identified and treated before the athlete is allowed to get back on the field. In the rare, but potentially lifesaving case that a major heart abnormality is found, athletes may be required to stop participation in sports. Why? Athletes routinely place their hearts and bodies under extreme stress. For those with certain heart abnormalities, there's an increased risk of sudden cardiac death, especially during intense periods of exercise, so avoiding extreme physical exertion can be lifesaving.

Although as athletes, we never want anything to stand between us and the sports we love, it's important to remember that, left ignored, heart abnormalities can and do prove fatal to athletes—even teen ones.

So this season, remember that pre-participation forms are more than a formality. Answering honestly about your family history as well as how you feel during exercise (think: Do you get dizzy? Does your heart race? Do you experience chest pain or shortness of breath?) can provide valuable insight into your heart health, keeping you safe on the field, and even improving your performance. And sometimes, yes, that might mean getting an ECG.


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