Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. The thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood.
Hypertrophic cardiomyopathy is a major cause of death in young athletes who seem completely healthy but die during heavy exercise.
Causes, incidence, and risk factors
The occurrence rate of HCM is 1 in 500 of the general population and is usually passed down through families (inherited). It is believed to be a result of several problems (defects) with the genes that control heart muscle growth.
Younger people are likely to have a more severe form of hypertrophic cardiomyopathy. However, the condition is seen in people of all ages.
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Fainting, especially during exercise
Heart failure (in some patients)
High blood pressure (hypertension)
Light-headedness , especially with or after activity or exercise
Sensation of feeling the heart beat (palpitations )
Shortness of breath
Other symptoms that may occur are:
Fatigue, reduced activity tolerance
Shortness of breath when lying down
The first symptom of hypertrophic cardiomyopathy among many young patients is sudden collapse and possible death. This is caused by very abnormal heart rhythms (arrhythmias), or from the blockage of blood leaving the heart to the rest of the body.
Signs and tests
Your health care provider will perform a physical exam and listen to the heart and lungs with a stethoscope. Listening with a stethoscope may reveal abnormal heart sounds or a murmur.
Tests used to diagnose heart muscle thickness, problems with blood flow, or leaky heart valves (mitral valve regurgitation ) may include:
24-hour Holter monitor (heart monitor)
Echocardiography (the most common test) with Doppler ultrasound
MRI of the heart
Transesophageal echocardiogram (TEE)
Some people with hypertrophic cardiomyopathy may not have symptoms and live a normal lifespan. Others may get worse gradually or rapidly. The condition may develop into a dilated cardiomyopathy in some patients.
People with hypertrophic cardiomyopathy are at higher risk for sudden death than the normal population. Sudden death can occur at a young age.
Hypertrophic cardiomyopathy is a well-known cause of sudden death in athletes. Almost half of deaths in hypertrophic cardiomyopathy happen during or just after the patient has done some type of physical activity.
If you have hypertrophic cardiomyopathy, always follow your doctor’s advice concerning exercise and medical appointments. Patients are sometimes advised to avoid strenuous exercise.
Contact your health provider if:
You have any symptoms of hypertrophic cardiomyopathy
You develop chest pain, palpitations, faintness, or other new or unexplained symptoms