Reed Miller

March 25, 2012

March 25, 2012 (Chicago, Illinois) — Doctors screening athletes for potentially lethal heart defects should follow ethnicity-specific guidelines in order to minimize false positives, results of a UK study show.

"The results of our study indicate that extrapolation of [European Society of Cardiology (ESC)] criteria derived solely from [white] cohorts to black athletic individuals will result in a huge number of athletes having a [false]-positive ECG, making ECG preparticipation screening completely impractical in this group," Dr Nabeel Sheikh (St George's University, London, UK) said during a session on athlete screening today at the American College of Cardiology 2012 Scientific Sessions.

"However, if we apply our refined criteria, we can take into account ethnicity-specific interpretations of T-wave inversion and also remove those [benign] abnormalities that black athletes commonly develop, which are most likely physiological according to our data, and we can reduce the number of positive ECGs significantly."

Sudden cardiac arrest among athletes is rare--about one in 44 000 athletes die suddenly each year, Sheikh said--but high-profile cases, like that of English soccer player Fabrice Muamba, have led many to call for widespread or mandatory preparticipation screening of all athletes, including ECGs. However, analysis of athlete ECGs can be difficult even for experienced physicians, and false-positive rates in these screenings can be as high as 10% to 20%, Dr Barry Maron (Minneapolis Heart Institute, MN) pointed out during the session.

A positive ECG alone does not always prevent an athlete from participating, but it necessitates follow-up testing, including echocardiography, and can create a lot of anxiety in the patient, so the false-positive rate of ECGs in preparticipation screening must be minimized for ECG screening of athletes to be feasible and cost-effective, Sheikh said.

Sheikh and colleagues found that screening in accordance with the latest ESC guidelines from 2010 yields a 45% abnormal ECG rate among black athletes but only a 13% abnormal rate among white athletes. That's an improvement over the 2005 guidelines, which yielded about 60% and 50% abnormal ECGs for black and white athletes, but it still suggests a high false-positive rate. Importantly, the difference between the white and black rates supports the mounting evidence showing that athletic exertion causes greater change to black athletes' hearts than white athletes' hearts, Sheikh said.

To create their more refined, race-specific screening guidelines, Sheikh et al analyzed ECGs from 923 black athletes, 1711 white athletes, and 209 patients with hypertrophic cardiomyopathy (HCM), the leading cause of sudden death in young athletes. The researchers' refined criteria reduced positive ECGs to 17% percent in black athletes and 5% percent in white athletes.

The previous ESC guidelines caught 100% of hypertrophic cardiomyopathy cases, while the refined guidelines caught 99.5% of these. In all but one case, the patients with HCM not detected by the ECG were identified based on family history or a regular physical exam.

Sheikh told heartwire that in addition to collecting long-term follow-up on these subjects, his group is collecting data on other ethnicities and groups within the broad white and black groups to further refine the screening guidelines.