Young athletes' ECGs frequently misinterpreted

Electrocardiograms (ECG) used to screen athletes for sports participation were misinterpreted more than 30% of the time by pediatric cardiologists who participated in a recent study.

When the 53 specialists were given tests of 8 young athletes with healthy hearts and 10 children with heart conditions that could lead to sudden cardiac arrest, they failed to restrict participation for almost 20% of the children with heart conditions and restricted more than 25% of children for whom playing sports posed little risk.

Interpretations by respondents had a false-positive rate of 30% and a false-negative rate of 32%. Computer-derived interpretations of the ECGs paralleled those of the cardiologists, correctly identifying 67% of the findings.

Results of the study challenge the wisdom of mandating ECGs before sports participation as several European countries have done and some groups have advocated in the United States. The American Heart Association has not supported the use of ECGs for prescreening because of the impracticality of prescreening the 10.7 million young people who play sports in this country and instead recommends a thorough history and physical every 2 years.

The study used an online questionnaire sent to 212 members of the Western Society for Pediatric Cardiology; 25% completed the survey. Of those, 43% read more than 100 ECGs per month.

Of the patients at risk of sudden cardiac death, 4 had hypertrophic cardiomyopathy, 2 had Wolff-Parkinson-White syndrome, 2 had myocarditis, 1 had pulmonary arterial hypertension, and 1 had long QT syndrome. The typical findings for each condition were present on the ECGs. Normal ECGs included some conditions common in hearts of athletic children such as sinus arrhythmia, low atrial rhythm, and sinus bradycardia. The cardiologists were given the age and sex of each patient but no further information.

Researchers noted that as athletes’ hearts grow stronger, they may get somewhat larger and beat more slowly, which may look similar on ECGs to defects that predispose people to sudden cardiac death.

Researchers cautioned that if prescreening ECGs are recommended by sports organizations, then the cardiologists should receive additional training and the criteria to be used for interpretation. Inclusion and exclusion also should be well defined.

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