Exercise-Induced Cardiac Remodeling in the WNBA: Defining Normal for Elite Female Basketball Players

Jul 20, 2020   |  Allison R Zielinski, MD, FACC

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Quick Takes

  • Women have been underrepresented in previous studies of athletic cardiac remodeling, and much of the existing data come from White European cohorts of non-basketball players. Given that physiologic remodeling depends on many factors, including gender, body size, ethnicity, type, and dose/intensity of sport, this echocardiographic study of 140 predominantly African American elite female basketball players helps define what is normal in this population.
  • Many of the athletes' cardiac dimensions exceeded cutoffs by ASE guidelines, but chamber sizes were proportional to body size (BSA). Indexed values for LVEDD rarely exceeded 3.1 cm/m2.
  • This study confirms that LV wall thickness rarely exceeds 1.2 cm in women, and aortic root size, while proportional to BSA, rarely exceeds 3.7 cm (even in this tall cohort).

Editor's Note: Commentary based on Shames S, Bellow NA, Schwartz A, et al. Echocardiographic characterization of female professional basketball players in the US. JAMA Cardiol 2020;Jun 24 [Epub ahead of print].1

Study Questions: To characterize the spectrum of cardiac structure and function of professional female basketball players using trans-thoracic echocardiography.

Methods:
In this cross-sectional study, the authors examined echocardiographic data from 140 elite female basketball players in the Women's National Basketball Association (WNBA) from the 2017 season. Complete rest and stress echocardiograms are performed annually prior to the start of the season. Left and right ventricular(L/RV) dimensions, left and right atrial size, LV mass and wall thickness, presence of LV hypertrophy, and aortic diameter were collected and analyzed for associations with body size (BSA) using linear regression.

Results:
The mean age of the athletes was 26.8 [3.9] years, with a mean height of 183.4 [9.0] cm, and mean BSA 2.02 [0.18] m2. Seventy-five percent (105/140) were African American. Mean heart rate was 56 [8] bpm, and mean BP was 116 [11]/70 [8] mm Hg. LV chamber enlargement (LVEDD >5.2 cm) was present in 36 (26.0%) of athletes, RV enlargement (RV basal dimension >4.2 cm) was present in 57 (42.2%). Left atrial (LA) dilation (LA volume index >34.0 ml/m2) was present in 57 (40.7%), and right atrial (RA) enlargement (RA volume index >33 ml/m2), in 25 (18.2%).

Maximal wall thickness ranged from 0.6-1.4 cm. While 78 (55.7%) had wall thickness of 1.0 cm or greater, only one athlete (0.7%) had a wall thickness of greater than 1.3 cm. Left ventricular hypertrophy (LVH, mass index >95 g/m2) was present in 23 athletes (16.4%). Of the athletes with LVH, 16 had eccentric LVH (69.6%), 7 had concentric LVH (30.4%). Of the athletes with normal LV mass index, 27 had concentric remodeling (23.1%).

LVEDD, RV basal dimension, LA and RA volumes, and LV mass correlated linearly with BSA. Aortic size also correlated linearly with BSA, although aortic root dimension above 4.0 cm was rare (2 athletes, 1.4%). One athlete had a bicuspid valve with borderline abnormal aortic dimension of 3.7 cm.

Mean left ventricular ejection fraction (LVEF) was 55.7% (95% CI, 55.1-56.3%), and 21 athletes (15.0%) had an EF of less than 52%, 4 (2.9%) had an EF less than 50%. All athletes had normal diastolic function at rest and normal augmentation of LV with exercise.

Conclusions:
Increased chamber sizes and wall thickness in WNBA athletes are common and a function of both BSA and exercise-induced cardiac remodeling. LV and RV chamber sizes correlated with body size. LV wall thickness of 1.3 cm or greater is rare and should warrant exclusion of pathology. Aortic root size also correlated with BSA although exceeded 3.7 cm in only a small percentage of athletes.

Perspective:
This is the largest cohort of sports-specific high-level female athletes and adds to the knowledge base of what is normal physiologic remodeling in this population. Basketball is a moderate static, high dynamic activity, and in these tall athletes (mean height 6 feet), increased cardiac chamber size and mild increase in LV wall thickness was common.

The cohort was 75% African American, and previous studies2 have demonstrated increased LV wall thickness compared to White athletes, although the LV wall thickness in the WNBA rarely exceeded 1.3 cm. This study was not powered to examine differences in dimensions by race/ethnicity, but it is an important finding that regardless of race/ethnicity, level of conditioning, or body size, LV hypertrophy in women greater than 1.3 cm should warrant exclusion of pathology (i.e. hypertrophic cardiomyopathy). It is also interesting that the authors found a greater percentage of concentric geometry than previously published data from White UK athletes;3 whether this is a function purely of sport-type alone remains uncertain.

Mildly reduced ejection fraction in high dynamic/mixed athletes can be normal, provided that diastolic parameters and augmentation of the ventricle with exercise/stress are preserved.

References

  1. Shames S, Bellow NA, Schwartz A, et al. Echocardiographic characterization of female professional basketball players in the US. JAMA Cardiol 2020;Jun 24 [Epub ahead of print].
  2. Rawlins J, Carre F, Kervio G, et al. Ethnic differences in physiologic cardiac adaptation to intense physical exercise in highly trained female athletes. Circulation 2010;121:1078-85.
  3. Finocchiaro G, Dhutia H, D'Silva A, et al. Effect of sex and sporting discipline on LV adaptation to exercise. JACC Cardiovasc Imaging 2017;10:965-72.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Sports and Exercise Cardiology, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Sports, Hypertrophy, Left Ventricular, Basketball, Stroke Volume, Cross-Sectional Studies, Mitral Valve, Linear Models, Ventricular Remodeling, Athletes, Atrial Fibrillation, Dilatation, African Americans, Heart Rate, Ventricular Function, Left, Female


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