Research on Race and Athletes Finds Heart Differences

By Paula Rasich
Reviewed by Elizabeth Klodas, MD, FACC

(CardioSmart) Should pre-participation health screening of all young athletes include an electrocardiogram (ECG)? An ECG is often the first step in detecting heart problems. Undiagnosed heart conditions raise the odds for sudden cardiac death in athletes. Although very rare, a death on the athletic field is devastating, especially if it could have been prevented.

Some European countries require the screening for all athletes beginning in high school, but American experts don’t believe that standard is practical. Two new studies published in the June 10th issue of the Journal of the American College of Cardiology throw a wrench into the debate.

To investigate ECG patterns in a diverse group of athletes, a team of researchers led by Anthony Magalski, MD, medical director of the Athletic Heart Clinic at Saint Luke’s Mid-America Heart Institute in Kansas City, Missouri, collected data on 1,959 college-aged football players attending the National Football League Invitational Camp between 2000 and 2005. Sixty-seven percent of the men were black.

Though abnormal ECG changes were detected in 25% of the total study population, they were twice as common in black athletes (30%) as compared to white athletes (13%). In addition, 6% of black athletes had very abnormal ECGs, compared to 2% of white players. To see if the very abnormal ECGs indicated the presence of heart disease, researchers gave 38% of those athletes a cardiac ultrasound (echocardiogram). The ultrasounds did not detect any heart problems, indicating that the ECG findings were, in fact, misleading.

The explanation for the racial differences in ECG patterns remains unclear. “Race seems to be an important determinant of abnormal ECG patterns, but after further evaluation by echocardiogram, the ones we studied did not have structural heart disease,” Dr. Magalski says.  “Although there are more ECG abnormalities in blacks than whites, there was no evidence that they have more heart problems or heart disease.” 

In a second study, researchers led by Sandeep Basavarajaiah, MBBS, from the King’s College Hospital in London, compared ECG and echocardiogram test results of 300 young, professional black athletes with 300 white male athletes matched for age, size, and type of sporting activity. The researchers found that 18% of black athletes displayed heart muscle thickening, compared to 4% of white athletes, and were much more likely to have abnormal ECG results. They also found that, for any sporting activity, black athletes were more likely to have substantially thicker heart muscle than their white counterparts.

Heart muscle thickening is a component of hypertrophic cardiomyopathy (HCM), a relatively uncommon condition, which can cause sudden death. Specific thickness cut-offs are currently used to help differentiate heart muscle thickening based upon athletic adaptation from true HCM, but those cut-offs are primarily based upon data from white athletes. The researchers speculate that heart muscle changes associated with intense physical training in black athletes are unique and could potentially generate inaccurate diagnoses of HCM in pre-participation screening programs. Those inaccurate diagnoses could disqualify some healthy black athletes from competitive sports.

How does this new data shape the debate? In an accompanying editorial, Antonio Pelliccia MD, from the Institute of Sports Medicine and Science in Rome, Italy, advocates establishing new definitions of what constitutes normal heart adaptation in athletes, based upon race, gender, and type of sporting activity. Considering these variables should help identify young athletes truly at risk for sudden death, while at the same time preventing inappropriate disqualification of athletes from the many opportunities associated with athletic pursuits. However, to arrive at the new definitions, a wider screening program may be needed.

Sources:

Anthony Magalski, MD, Medical Director of the Athletic Heart Clinic at the Mid-America Heart Institute in Kansas City, MO., and consulting cardiologist for the Kansas City Chiefs pro football team.

Magalski et al.  Relation of Race to Electrocardiographic Patterns in Elite American Football Players.  Journal of the American College of Cardiology 2008.

Basavarajaiah et al. Ethnic Differences in Left Ventricular Remodeling in Highly Trained Athletes.  Journal of the American College of Cardiology 2008.

Pelliccia.  Differences of Cardiac Remodeling Associated with Race.  Journal of the American College of Cardiology 2008.