For the first time, cardiologists have characterized the adaptive cardiac remodeling in a large cohort of National Basketball Association players, which establishes a normative database and allows physicians to distinguish it from occult pathologic changes that may precipitate sudden cardiac death, according to an imaging study.
“We hope that the present data will help to focus decision making and improve clinical acumen for the purpose of primary prevention of cardiac emergencies in U.S. basketball players and in the athletic community at large,” said Dr. David J. Engel and his associates of Columbia University, New York.
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Until now, most of the literature concerning the structural features of the athletic heart has been based on European studies, where comprehensive cardiac screening of all elite athletes is mandatory. The typical sports activities and the demographics of athletes in the U.S. are different, and their cardiologic profiles have not been well studied because detailed cardiac examinations are not compulsory. But the NBA recently mandated that all athletes undergo annual preseason medical evaluations including stress echocardiograms, and allowed the division of cardiology at Columbia to assess the results each year.
“A detailed understanding of normal and expected cardiac remodeling in U.S. basketball players has significant clinical importance given that the incidence of sports-related sudden cardiac death in the U.S. is highest among basketball players and that the most common cause ... in this population is hypertrophic cardiomyopathy,” the investigators noted.
Their analysis of all 526 ECGs performed on NBA players during a 1-year period “will provide an invaluable frame of reference to enhance player safety for the large group of U.S. basketball players in training at all skill levels, and in the athletic community at large,” they said.
The study participants were aged 18-39 years (mean age, 25.7 years). Roughly 77% were African American, 20% were white, 2% were Hispanic, and 1% were Asian or other ethnicities. The mean height was 200.2 cm (6’7”).
Left ventricular cavity size was larger than that in the general population, but LV size was proportional to the athletes’ large body size. “Scaling LV size to body size is vitally important in the cardiac evaluation of basketball players, whose heights extend to 218 cm and body surface areas to 2.8 m2,” Dr. Engel and his associates said (JAMA Cardiol. 2016 Feb 24. doi: 10.1001/jamacardio.2015.0252).
Left ventricular hypertrophy (LVH) was identified in only 27% of the athletes. African Americans had increased indices of LVH, compared with whites, and had a higher incidence of nondilated concentric hypertrophy, while whites showed predominantly eccentric dilated hypertrophy. These findings should help clinicians recognize genuine hypertrophic cardiomyopathy, which is a contraindication to participating in all but the most low-intensity competitive sports.
Most of the participants had a normal left ventricular ejection fraction, and all showed normal augmentation of LV systolic function with exercise.
Aortic root diameter was larger than that in the general population but similar to that in other elite athletes. Surprisingly, aortic root diameter increased with increasing body size only to a certain point, reaching a plateau at 31-35 mm. Fewer than 5% of the participants had an aortic root diameter of 40 mm or more, and the maximal diameter was 42 mm. “These data have important implications in the evaluation of exceptionally large athletes and question the applicability in individuals with significantly increased biometrics of the traditional formula to estimate aortic root diameter that assumes a linear association between [it] and body surface area,” they noted.
“We hope that the results of this study will assist recognition of cardiac pathologic change and provide a framework to help avoid unnecessary exclusions of athletes from competition. We believe that these data have additional applicability to other sports that preselect for athletes with height, such as volleyball, rowing, and track and field,” Dr. Engel and his associates added.
This study was supported by the National Basketball Association as part of a medical services agreement with Columbia University. Dr. Engel and his associates reported having no relevant financial disclosures.