We are writing in reference to the report by Caselli et al that proposes a new criterion for differentiating left ventricular hypertrophy (LVH) seen in athletes from hypertrophic cardiomyopathy (HC) using a left ventricular cavity size cut-off value of <54 mm to assist in diagnosis. It appears that this is the first time a reliable criterion has been identified to differentiate athletes in the gray zone for LVH from patients with HC with a 100% sensitivity and specificity. We recognize the challenges with recruiting athletes with LVH in the gray zone, as 1,191 potential participants were evaluated for inclusion in the study with only 28 participants selected.

The study consisted of 28 Italian athletes being compared with 25 US-based patients with HC (23 Caucasian and 2 African-American), which raises concerns as to whether the Italian population is directly comparable with a US-based patient population. The investigators also stated that the athletes were matched for age and gender but because all athletes were male, this may not apply to female athletes. Given that HC affects men and women equally, future studies may need to consider including women in the study population.

The prevalence of sudden death from HC in the United States is higher among black athletes, a population group that has a significantly thicker left ventricular wall compared with white athletes, and therefore, they are more likely to be misdiagnosed with HC using the current criteria by the American College of Cardiology Foundation/American Heart Association Task Force. In addition, black athletes have been shown to have larger left ventricular cavities than white athletes.

This report by Caselli et al has the potential to have a significant social and economic impact in the US sports world. However, these results may not be completely applicable in the United States, where blacks constitute a large proportion of athletes participating at the national level. In 2012 to 2013, African-Americans comprised the majority of all National Basketball Association and National Football League players, 76.3% and 66.3%, respectively, with the exception of Major League Baseball where white players are a majority (61.2%).

Based on the study done by Basavarajaiah et al, black sedentary controls who did not have a diagnosis of HC had left ventricular cavity size ranging from 28 to 55 mm, which suggests that a cut-off value of <54 mm might not be suitable for black subjects. It will be interesting to see whether black patients with HC have a larger left ventricular cavity compared with white patients with HC. In conclusion, we are calling for the need to include black athletes, matched for age, race, and gender, in future studies aimed at differentiating athletes with LVH in the gray zone from HC.