Munson Health
Hypertrophic Cardiomyopathy -- Adult

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by Kohnle D

(Cardiomyopathy, Hypertrophic—Adult; HCM—Adult; Idiopathic Hypertrophic Subaortic Stenosis—Adult; Asymmetric Septal Hypertrophy—Adult; ASH—Adult; HOCM—Adult; Hypertrophic Obstructive Cardiomyopathy—Adult)



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 neighboring 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:
  • Dilated
  • Hypertrophic—can be divided into two types:
    • Hypertrophic obstructive cardiomyopathy (HOCM)—the muscle between the two valves of the heart becomes so enlarged that it obstructs the blood flow in the heart
    • Non-obstructive hypertrophic cardiomyopathy—non-obstructive form, the enlarged muscle is not large enough to block blood flow
  • Restrictive
HCM can occur in people of all ages. But, it is usually most severe when it occurs in younger people. The diagnosis is only made in people who do not have other causes of cardiomyopathy (eg, amyloidosis , sarcoidosis , coronary or valvular heart disease, etc.)
Those with HCM are at an increased risk of sudden death. However, many individuals with HCM live a normal, healthy life with very few symptoms.
Normal Heart and Heart With Hypertrophic Cardiomyopathy
Hypertrophic Cardiomyopathy
Copyright © Nucleus Medical Media, Inc.


Your doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include the following:
  • Stress test —tests how the body responds to exercise, which can help in detecting heart and lung problems
  • Echocardiography —uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
  • Transesophageal echocardiogram —images of the heart are taken to detect abnormalities
  • Heart monitor—a portable electrocardiogram (ECG) records continuous heart activity usually over a 24-72 hour period to determine regularity of the heartbeat
  • Heart catheter—a catheter is inserted into an artery in the groin area and threaded to the heart chambers
    • An x-ray machine shows real-time images of your body as a dye is injected through the catheter. This allows angiograms (photos) to be taken of the blood vessels and the heart.
  • Blood tests
  • Chest x-ray —uses radiation to take a picture of structures inside the body, especially bones.


American Heart Association

Cardiomyopathy Association



Canadian Cardiovascular Society

Heart and Stroke Foundation of Canada



American Heart Association. Cardiomyopathy. American Heart Association website. Available at: Accessed June 26, 2007.

Cleveland Clinic Heart and Vascular Institute. Hypertrophic cardiomyopathy. The Cleveland Clinic Heart and Vascular Institute website. Available at: Accessed June 26, 2007.

DynaMed Editorial Team. Hypertrophic cardiomyopathy. EBSCO DynaMed website. Available at: Updated October 25, 2010. Accessed November 5, 2010.

Erwin JP, Nishimura RA, et al. Dual chamber pacing for patients with hypertrophic obstructive cardiomyopathy: a clinical perspective in 2000. Mayo Clin Proc . 2000;75:173-180.

The HCM Program. St. Luke's Roosevelt Hospital Center website. Available at: . Accessed June 26, 2007.

Maron BJ, Nishimura RA, et al. Assessment of permanent dual chamber pacing for patients with hypertrophic cardiomyopathy. Circulation. 1999;99:2927-2933.

Mayo Clinic. Hypertrophic cardiomyopathy. Mayo Clinic website. Available at: Updated March 25, 2009. Accessed November 5, 2010.

McCully RB, Nishimura RA, et al. Extent of clinical improvement after surgical treatment of hypertrophic obstructive cardiomyopathy. Circulation. 1996;94:467-471.


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