Faulty ECG readings may endanger young athletes

Misinterpreting the tests can lead to youths playing sports with underlying cardiac conditions, a study says.

By Christine S. Moyer, amednews staff. Posted Aug. 2, 2011.

Reports of sudden cardiac arrest in young athletes have led some health professionals to recommend mandatory electrocardiogram screening before youths can participate in sports. But these tests might not be effective in preventing sudden cardiac death, a study shows.

The study, published online July 15 in The Journal of Pediatrics, found that pediatric cardiologists regularly misinterpret ECGs, overlooking conditions that often underlie sudden cardiac death. Such conditions include hypertrophic cardiomyopathy and myocarditis.

"Screening tests are not infallible," said Anne M. Dubin, MD, senior study author and associate professor of pediatrics at Stanford University School of Medicine in California. "We're not saying you should or shouldn't screen [for indicators of sudden cardiac death]. But if [the country is] going to do this on a widespread public health realm, we need not only more doctors to do it, but they also need to be better trained in what exactly they're looking for."

About 300,000 sudden cardiac arrests occur in people who are not hospitalized each year, according to the Centers for Disease Control and Prevention. Most people who develop the condition die from it within minutes, said the National Heart Lung and Blood Institute.

Researchers sent an online questionnaire to 53 physicians who were members of the Western Society of Pediatric Cardiology. The survey tested the accuracy of ECG screening. The correct diagnoses were based on the survey responses of two pediatric electrophysiologists.

The questionnaire featured 18 ECGs from a database at Lucile Packard Children's Hospital in Palo Alto, Calif. There were eight cases of patients with normal hearts and 10 ECGs from individuals with conditions that commonly underlie sudden cardiac death.

Respondents received the age and sex of each patient. They were asked whether each ECG was normal, to describe their interpretation of the screen, what -- if any -- heart disease they thought the patient might have, what additional tests they would order and whether they would recommend allowing the patient to participate in athletic events.

Researchers found that respondents correctly identified 68% of the abnormal cases, leaving one in three youths with undetected irregular ECGs (www.ncbi.nlm.nih.gov/pubmed/21752393/). Of the cases that physicians did identify as abnormal, about 30% were actually normal.

Inaccurate interpretations led physicians to make faulty sports diagnoses for some patients, the study shows. For instance, 26% of individuals with normal ECGs were restricted from participating in sports. On the other hand, 19% of patients who should have been barred from sports participation were allowed to take part.

"Although other countries have enacted laws mandating ECG screening for their athletes, the difficulty of interpreting ECG results, combined with the very large population of young athletes in the United States -- more than 10.7 million -- may make such laws impractical," said lead study author Allison C. Hill, MD.