Hypertrophic cardiomyopathy (HCM) is a genetic heart condition that can affect individuals of any age, including those who are physically active. This condition involves changes to the heart muscle, impacting its ability to function normally. Understanding HCM is particularly relevant for athletes, as physical exertion can influence its manifestation and risks.
What is Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy is a condition where the heart muscle becomes abnormally thick. This thickening often occurs in the left ventricle, the heart’s main pumping chamber. The increased muscle mass makes it more challenging for the heart to pump blood effectively throughout the body.
The thickened walls can also stiffen, reducing the amount of blood the heart can fill with each beat. This can lead to abnormal electrical activity within the heart. HCM is recognized clinically by a maximal left ventricular wall thickness of 13 mm or greater.
Why HCM is Risky for Athletes
HCM is risky for athletes. It is a leading cause of sudden cardiac death (SCD) in young athletes under 35 years of age. Exercise can worsen the condition by increasing heart rate and blood pressure.
This increased stress can lead to dangerous heart rhythm abnormalities, such as ventricular fibrillation, or obstruction of blood flow from the heart. The risk of SCD in young athletes with HCM is higher in those participating in high-intensity sports like basketball, soccer, and American football. While moderate exercise may be beneficial for older patients with HCM, high-intensity training in younger athletes with the condition may trigger dangerous heart rhythms.
Identifying and Managing HCM in Athletes
Diagnosing HCM in athletes presents a challenge because exercise can cause physiological changes in the heart that mimic the condition, known as “athlete’s heart”. Diagnosis begins with a detailed medical history and physical examination, looking for symptoms, family history of heart conditions, or unexplained sudden deaths.
Diagnostic tools include:
Electrocardiograms (ECGs) detect characteristic changes in over 90% of cases.
Echocardiograms visualize the heart’s structure and function, though distinguishing HCM from an athlete’s heart can be complex.
Cardiac magnetic resonance imaging (CMRI) helps identify indicators of HCM by revealing focal hypertrophy and fibrosis.
Genetic testing can identify hereditary factors, though it is not a routine screening method.
Management strategies for athletes diagnosed with HCM are individualized based on the condition’s severity and specific risk factors. These include:
Medications like beta-blockers and calcium channel blockers to manage symptoms and improve heart function.
Lifestyle modifications, including limiting certain types of physical activity.
An implantable cardioverter-defibrillator (ICD) for individuals at higher risk of sudden cardiac events, to deliver an electrical shock if a dangerous arrhythmia occurs.
Surgical procedures like septal myectomy, which removes a portion of the thickened heart muscle, to improve blood flow.
Athletes and Sports Participation
Historically, individuals with HCM have been advised against participation in vigorous competitive sports due to concerns about sudden cardiac death. Guidelines from organizations such as the American Heart Association and the American College of Cardiology have recommended restricting competitive sports participation for those with HCM to low-intensity activities like golf or bowling. This recommendation is based on the understanding that intense physical exertion can increase susceptibility to sudden cardiac events.
Recent data and evolving guidelines are shifting towards a more individualized approach for athletes with HCM. While the risk of sudden cardiac death during exercise is acknowledged, some data suggest that individuals with HCM who participate in vigorous sports may not have an increased arrhythmic risk compared to less active individuals. Decisions about sports participation are now made in collaboration with a specialized cardiologist, considering the athlete’s specific condition, risk factors, and personal preferences. Low-intensity or recreational activities under strict medical supervision may be discussed, but participation in most competitive or high-intensity sports remains restricted.