ECG Findings in NBA Athletes

Study Questions:

What is the prevalence of normal and abnormal electrocardiographic (ECG) findings when using the latest athlete’s ECG criteria in National Basketball Association (NBA) basketball players?

Methods:

This was a retrospective analysis of NBA-mandated preseason ECGs and stress echocardiograms. All athletes participating in the 2013-14 and 2014-15 NBA seasons, and all participants in the 2014 and 2015 predraft combines, formed the study group. ECG analysis was initially performed by at least two investigators using the three most recent ECG criteria: the Seattle criteria, the Refined criteria, and the International recommendations published earlier this year. All ECG findings were then readjudicated by two of the investigators. Standard echocardiographic views were obtained. Left ventricular (LV) mass and LV relative wall thickness (RWT) were also calculated. Two-tailed t-test, Fischer exact test, and analysis of variance were used for statistical analysis.

Results:

A total of 519 players had paired ECGs and echocardiograms for review, 505 of which (African American, n = 409, and Caucasian, n = 96) formed the subgroup on race. Of the physiologic, training-related (“green light”) findings in all athletes, 89% had any ECG change; early repolarization was most prevalent (69.7%) followed by LV hypertrophy (35.3%) and sinus bradycardia (28.7%). Convex ST elevation with T-wave inversion in leads V1-V4, thought to be training-related findings in African American or African Caribbean athletes, was seen in 5.4% in subgroup analysis.

Of the abnormal (“red light”) ECG findings, the International recommendations had the lowest rate of abnormal classification (15.6%). Older athletes were more likely to manifest abnormal findings. Amongst all athletes, abnormal T-wave inversion was most common (6.2%), followed by ≥2 borderline (“yellow light”) findings (5.6%) and long QTc interval (4.8%). The majority of the borderline findings were attributed to left or right atrial enlargement. RWT was the only echo parameter that was significantly associated with an abnormal ECG classification. Moreover, the presence of T-wave inversion on ECG was significantly associated with increased RWT and decreased LV end-diastolic diameter.

Conclusions:

Using the most recent ECG criteria, the prevalence of ECG abnormalities in this observational cohort of NBA basketball players was lower, but still relatively high compared to prior studies of heterogeneous sport-types. Further work is needed to elucidate the importance of repolarization abnormalities (i.e., T-wave inversion, long QTc interval) in athletes. Longitudinal data on training-related ECG changes are forthcoming.

Perspective:

This is a unique study of young, male, mostly African American NBA players and a follow-up to a 2016 study of heart structure in NBA players from some of the same investigators. Some important take-home messages include:

  1. Physiologic changes consistent with training were very common (89%).
  2. The latest (International recommendations) ECG criteria had the lowest rate of abnormal findings.
  3. Studies such as this will frame further study and recommendations on normal versus abnormal T-wave inversion and repolarization patterns in highly trained athletes.
  4. Still more research is needed to define normal versus abnormal ECG findings specific to sport-type (including different position within the same sport), gender, and race.
  5. The clinical significance of small LV cavity size, increased RWT, and/or T-wave inversion is not clear. Are these training-related or independent of basketball? Repeated measurements and longitudinal follow-up may provide more answers.
  6. Of note, no athletes were reported as having findings that warranted disqualification from participation.

Clinical Topics: Arrhythmias and Clinical EP, Noninvasive Imaging, Sports and Exercise Cardiology, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound, Sports & Exercise and Imaging

Keywords: Arrhythmias, Cardiac, Athletes, Basketball, Bradycardia, Diagnostic Imaging, Echocardiography, Stress, Electrocardiography, Hypertrophy, Sports Medicine


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