Subspecialist Consult

Putting ECGs to the Test


 

Electrocardiography to test a child’s heart prior to sports participation can help identify some – but not all – causes of sudden cardiac death.

Offering this test is not without debate, however, whether your patient is a young athlete about to start a sports program or a student about to start stimulant medication for attention-deficit/hyperactivity disorder.

Your clinical judgment remains paramount, as ECG screening before sports is not mandated in the United States, but placing your patient in one of the following three categories can help guide diagnosis and management:

Photo courtesy Loyola University Chicago Stritch School of Medicine

Dr. Neeru Jayanthi

Asymptomatic child, normal physical exam. Most of the patients you see for a sports evaluation will be asymptomatic. Perform the physical examination and take a thorough history, with a specific look for any signs of sudden cardiac death such as family history or previous symptoms. In general, this evaluation will suffice and you will not need to order blood assays or other tests. If you want to augment your evaluation by ordering an ECG, you will be ahead of the curve. Most pediatricians manage these kids whether they order an ECG or not. If you’re uncertain or uncomfortable for any reason at this point, consider referral.

Symptomatic child. Children in this group may describe palpitations, chest pain, and/or an instance when they felt they were about to pass out (syncope or presyncope). The symptomatic child should be evaluated further if you have any clinical concerns, and ECG is a good starting point. Unless you feel very comfortable, consider specialist consultation and comanagement of these patients. Watch especially for exercise-related syncope. For me, passing out with exercise is a red flag because it’s one of the few specific signs of structural heart disease. At a minimum, evaluations of rhythm (ECG) and structure (echocardiography) are indicated, and sometimes an electrophysiology work-up can be helpful.

Asymptomatic child, some examination findings. Some asymptomatic children have a potentially relevant clinical finding, such as a murmur. Most innocent murmurs are monitored appropriately in the primary care setting, but referral is more strongly suggested for murmurs of concern, which include holosystolic murmurs, grade 3-6 murmurs, and diastolic murmurs. An ECG is still an excellent starting point, but you have a choice. Some pediatric cardiologists also would recommend an echocardiogram or just a referral to them for further work-up. You don’t always have to rush to echocardiography. (Some would argue there are too many echoes ordered right off the bat, and I think there are too few initial ECGs ordered.)

Much of your management strategy depends on your comfort level. Most pediatricians can read an ECG and immediately know that something is not right if they see a significantly prolonged QT interval or WPW (Wolff-Parkinson-White syndrome) changes. I’ve learned, however, that most of the pediatricians at our institution would be uncomfortable making the call regarding some of the more subtle ECG findings. Many pediatricians’ offices do not have ECG equipment, so the patient will be sent elsewhere anyway.

Screening Before an ADHD Regimen

Consideration of ECG screening also comes up prior to prescription of an ADHD stimulant medication.

Unfortunately, a small number of deaths have been associated with use of these medications. Some of those patients had underlying congenital and structural heart disease that some believe could have been identified with a simple ECG. Most people would agree to some sort of cardiovascular monitoring, such as blood pressure or heart rate measurements. Complicating matters is the increased risk of ADHD in children with congenital heart anomalies.

Proceeding with an ECG screen doesn’t rule out prescribing the ADHD medicine, according to the recommendation, but it might be worthwhile to have a pediatric cardiologist manage any particular clinical concerns.

False-Positive Results

ECGs are safe and very inexpensive if you already have the equipment. The biggest debate about ECGs in the world of sports medicine centers on high false-positive rates. Depending on how the ECG is read and which criteria you use, the false positive rate can be as low as 2% or as high as 15%. Using the right criteria removes some of the unnecessary false positives and can reduce the rate to a more acceptable 2%-5%. In my opinion, that rate is low enough to justify offering low-cost ECGs for those who would like to be screened.

Interestingly, some of the false-positive findings are not as concerning among young athletes. Examples are an incomplete right bundle branch block, early repolarization, isolated QRS voltage criteria for left ventricular hypertrophy, and first-degree atrioventricular block. Some experts argue that if we remove these specific findings, we will be left primarily with the most concerning ones and thus can improve the false-positive rate.

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