Hypertrophic cardiomyopathy screening

Hypertrophic cardiomyopathy, or HCM, is the leading cause of sudden cardiac death (SCD) in young athletes. HCM is frequently asymptomatic until SCD, and thus its prevention requires screening. Screening by medical history and physical exam are mostly ineffective, indicating heart abnormalities in only 3% of patients who subsequently suffered SCD. However, HCM can be detected with 80%+ accuracy by echocardiogram (ECHO), which may be combined with pre-screening by electrocardiogram (ECG). Routine cardiac screening of athletes has been implemented in Italy since 1982, and has resulted in an 89% drop in the incidence of SCD among screened athletes, from an unusually high starting rate. In the United States, citing cost concerns and low incidence, the American Heart Association has consistently opposed such routine screening. For rare conditions like HCM, the rate of false positive testing is also a significant concern. However, certain chapters of the American College of Cardiology are backing screening models provided by private entities and nonprofit organizations. Screen-positive individuals who are conclusively diagnosed with cardiac disease are usually told to avoid competitive athletics.

HCM is a genetic disorder that causes the muscle of the heart (the myocardium) to thicken (or hypertrophy) without any apparent reason. When the heart thickens and becomes enlarged, particularly at the septum and left ventricle, it can cause dangerous arrhythmias (abnormal heart rhythms). The thickening of the heart also makes it harder for blood to leave, forcing the heart to work more vigorously to pump blood.

HCM occurs in approximately 2 per 1,000 people in the general population, being a primary and familial malformation. While younger individuals are likely to have a more severe form of hypertrophic cardiomyopathy, the condition is seen in people of all ages. Studies have shown that HCM is the most common cause of sudden cardiac death in athletes, accounting for approximately one-third of cases. Almost half of these HCM deaths happen during or just after physical exertion. The disease is equally prevalent in males and females, but 90% of HCM deaths in athletes occur in males, potentially due to their higher frequency of participation at a higher intensity. 60% of athletes are of high-school age at the time of death.

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