Background Physical training can provoke electrocardiographic changes and echocardiographic left ventricular hypertrophy in a considerable proportion of black athletes but only a minority of white athletes. Consequently, differentiating “black athletes heart” and hypertrophic cardiomyopathy may be challenging. We evaluated the prevalence and significance of electrocardiographic repolarisation anomalies in highly trained black athletes and compared them to white athletes and hypertrophic cardiomyopathy patients in an attempt to differentiate physiology vs pathology.

Methods We analysed the electrocardiograms of 1759 male athletes (910 black athletes; 849 white athletes) who underwent preparticipation cardiovascular screening. Further cardiac evaluation was performed, where appropriate. Results were compared with those of 150 hypertrophic cardiomyopathy patients.

Results T-wave inversions were present in 76%, 25% and 7% of hypertrophic cardiomyopathy patients, black athletes and white athletes, respectively (p<0.001). The majority of hypertrophic cardiomyopathy patients (60%), a significant proportion of black athletes (12%) but only a minority of white athletes (0.7%) exhibited distinctly abnormal electrocardiograms, with deep T-wave inversions (≥0.2 mV), raising strong clinical suspicion of an underlying cardiomyopathy (p<0.001). Deep T-wave inversions in black athletes were primarily (65%) identified in contiguous anterior precordial leads (V1–V4) and were associated with convex ST-segment elevation. In contrast, 88% of deep T-wave inversions in hypertrophic cardiomyopathy patients were present in contiguous inferior and/or lateral leads and were associated with ST-segment depression. During follow-up (2.95±1.78 years, range: 1–8), 1 black athlete was diagnosed with hypertrophic cardiomyopathy and one survived a cardiac arrest. Both athletes exhibited deep T-wave inversions in contiguous inferior and/or lateral leads.

Conclusions Deep T-wave inversions with associated convex ST-segment elevation in leads V1–V4 appear to represent an ethnic variant of “athletes heart”, while deep T-wave inversions in inferior and/or lateral leads merit further cardiovascular investigations and regular follow-up.