UNDERSTANDING HYPERTROPHIC CARDIOMYOPATHY IN YOUNG ATHLETES

Abstract

Hypertrophic cardiomyopathy (HCM) is the most common cause of non-traumatic sudden cardiac death (SCD) for athletes under the age of 35, though it often goes undetected and undiagnosed until after death in these cases. In this literature review, I sought to examine the profiles of young competitive athletes, both who died from and are living with HCM, to determine if there is any way to better predict which athletes might be at higher risk for developing or dying from HCM. The demographic profiles of athletes with HCM, including gender and race, were examined, as well as the genetic drivers of HCM. Additionally, the disease presentation of HCM in non-athlete individuals was compared to those of athletes with HCM to investigate whether phenotype discrepancies were to blame for athlete cases going undiagnosed. After reviewing the current literature, it was found that among US collegiate athletes, men were much more likely to die from HCM than females, and that HCM death was more common among black athletes than white athletes. However, it is still unclear as to why this is the case. In terms of genetics, two genes are responsible for causing 80% of HCM cases when mutated, cMyBPC3 and MYH7, but there is currently no definitive genetic link between gender and/or race with HCM occurrence. When comparing athlete HCM patients with sedentary HCM patients, it was found that athletes do have a slightly different disease phenotype, including less severe hypertrophy, higher instances of apex hypertrophy rather than ventricular wall hypertrophy, better cardiac functionality, and better ventricular diastolic function. However, fibrosis severity was the same between the two groups. Future implications of these findings may include creating separate HCM diagnostic criteria for athletes versus the general population so that fewer athlete HCM cases go undiagnosed. Note: In order to provide a wider contextual understanding of the heart and to represent some of the knowledge I have developed as a physiology student over the past four years, the first half of this thesis is comprised of an overview of the cardiovascular system as a whole, as well as a general summary of hypertrophic cardiomyopathy.