What is it?
Hypertrophic cardiomyopathy (HCM) is a common, inherited cardiovascular disease that affects about one in 500 people. It is caused by a genetic mutation that occurs in the heart muscles. “Mutations” are changes within an individual’s DNA that can lead to improper functioning of the body’s cells that can be passed down through generations. HCM can lead to an enlarged heart that can make a person more likely to have an irregular heart beat (also known as an arrhythmia), a stroke, heart failure, or a heart attack.

Symptoms/Risks
People may have no symptoms, but there are those who just suddenly die. HCM is arguably the most common cause of sudden cardiac death in athletes in the United States, accounting for about 1/3 of the known causes of such deaths. It carries a <1% mortality rate per year. Symptoms of heart failure can occur, or one may develop a heart arrhythmia problem, such as atrial fibrillation, that can make it more likely for someone to have a stroke. Many people with HCM do not have any symptoms and can expect to have a relatively normal lifespan.

Sports Medicine Evaluation and Treatment
HCM is often diagnosed with an echocardiogram (an ultrasound of the heart) or a cardiac MRI. Patients with a family history of HCM may undergo genetic testing or get an echocardiogram to identify the condition. Treatment primarily depends on managing associated symptoms. An implantable cardioverter-defibrillator (ICD) is often used to hopefully prevent sudden cardiac death, and has helped to reduce the rate of death associated with this condition. This device is surgically placed under the skin to track one’s heartbeat and to detect abnormal beats. It can deliver a shock to stop abnormal heart beats if they occur. Heart transplants for severe heart failure, and other surgical procedures, may be considered also.

Injury Prevention
A screening physical examination can reveal abnormal exam findings. Abnormalities can be seen on an electrocardiogram (ECG), if this is obtained, that would lead a clinician to obtain an echocardiogram and further workup. Individuals who are diagnosed with this condition may be advised to take medications, such as beta blockers, or receive an ICD, to prevent sudden cardiac death.

Return to Play
In previous years, expert opinion recommended that: (1) athletes who have genetic evidence for the disease, but lack findings of an enlarged heart on echo or cardiac MRI, and do not have any cardiac symptoms can participate in competitive athletics after an informed decision is agreed upon by the athlete, his physician, and the team; and (2) athletes diagnosed with HCM who have evidence of an enlarged heart should not compete in competitive sports with the exception of low intensity sports such as billiards, bowling, golf, cricket, curling, and riflery. However, recent 2015 American College of Cardiology and American Heart Association guidelines suggest that an athlete with an ICD can participate in sports if no shocks to correct arrythmia have occurred within three months. Assuming the athlete has been medically or surgically managed appropriately, and the athlete and family are informed of an increased risk of both appropriate and inappropriate shocks with sport, as well as a small but real risk of ICD failure, then, ultimately, the final decision in regards to return to play should lie with the athlete and his or her family.

AMSSM Member Authors
Scott Annett, MD and Irfan Asif, MD

References
Maron B, Udelson J, Bonow R, et al. Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: Task Force 3: Hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and other cardiomyopathies, and myocarditis. A scientific statement from the American Heart Association and American College of Cardiology. J Am Coll Cardiol. 2015;66(21):2362-2371. doi:10.1016/j. jacc.2015.09.035

Prutkin JM, Ackerman MJ, Drezner JA. Athletes with implantable cardioverter defibrillators: can they return to competitive sports? Heart 2016 102: 93-94. doi: 10.1136/heartjnl-2015-309152rep