Hypertrophic cardiomyopathy, or HCM, is a form of
cardiomyopathy. This is a condition in which the heart muscle thickens due to genetic problems with the muscle’s structure. As the muscle thickens, it must work harder to pump blood, which strains the heart muscle. Sometimes, the thickened muscle gets in the way of the blood leaving the heart and causes a blockage. This blockage can cause the nearby heart valve, called the mitral valve, to become leaky. HCM can cause uneven muscle growth which can cause the heart to pump in a disorganized way. Rarely, it can cause abnormal heart rhythms that can even be fatal.
There are three main types of cardiomyopathy:
Causes of HCM include:
In people over age 60, HCM is likely to be caused by or related to
high blood pressure.
HCM can occur in people of all ages. But, it is usually most severe when it occurs in younger people.
These factors increase your chance of developing this condition. Tell your doctor if you have any of these risk factors:
These symptoms can be caused by some of the side effects of the condition, including
(abnormal heart beats). The blocked or reduced blood flow is usually the cause of symptoms like lightheadedness, fainting, and difficulty breathing.
You will be asked about your symptoms and medical history. A physical exam will be done.
Your bodily fluids may be tested. This can be done with blood tests.
Your body's response to exercise may be tested. This can be done with a stress test.
Images may be taken of your bodily structures. This can be done with:
Your heart activity may be monitored. This can be done with a portable electrocardiogram (ECG).
The diagnosis is only made in people who do not have other causes of cardiomyopathy such as amyloidosis,
or valvular heart disease.
Those with HCM are at an increased risk of sudden death. However, many individuals with HCM live a normal, healthy life with few symptoms.
Treatment focuses on controlling symptoms and preventing complications. Talk with your doctor about the best treatment plan for you. Treatment options include:
Medications may be used to help maintain proper and regular heart function. These may include beta-blockers and calcium channel blockers.
If you have an arrhythmia, you may need anti-arrhythmic drugs. You may also need blood-thinning medication.
The thickened portion of the heart muscle is cut and removed. This may be needed if you have severely blocked blood flow from the heart.
If the mitral valve is leaking, surgery may also be done to repair or replace the mitral valve.
Alcohol is injected into the arteries of the thickened portion of the heart. This helps to reduce the blockage in the heart and improve blood flow out of the heart.
is implanted if you are at increased risk for sudden death.
To help reduce your chances of getting HCM, take the following steps:
American Heart Association
Canadian Cardiovascular Society
Heart and Stroke Foundation of Canada
Cardiomyopathy in adults. American Heart Association website. Available at:
Accessed September 30, 2014.
Erwin JP, Nishimura RA, et al. Dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy: a clinical perspective in 2000.
Mayo Clin Proc
Hypertrophic cardiomyopathy. EBSCO DynaMed Plus website. Available at:
http://www.dynamed.com/topics/dmp~AN~T115426/Hypertrophic-cardiomyopathy. Updated March 20, 2016. Accessed September 28, 2016.
Maron BJ, Nishimura RA, et al. Assessment of permanent dual chamber pacing for patients with hypertrophic cardiomyopathy.
McCully RB, Nishimura RA, et al. Extent of clinical improvement after surgical treatment of hypertrophic obstructive cardiomyopathy.
What is HCM? St. Luke's Roosevelt Hospital Center website. Available at:
Accessed September 30, 2014.
Last reviewed August 2014 by Michael J. Fucci, DO
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