Hypertrophic cardiomyopathy (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 2 types of hypertrophic cardiomyopathy:
- Hypertrophic obstructive cardiomyopathy (HOCM)—the muscle between the 2 valves of the heart becomes so enlarged that it obstructs the blood flow in the heart
- Nonobstructive hypertrophic cardiomyopathy—nonobstructive form, the enlarged muscle is not large enough to block blood flow
|Normal Heart and Heart with Hypertrophic Cardiomyopathy|
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Causes of HCM include:
- A gene that causes the abnormal structure of the heart muscle. It can be inherited or can happen from changes in the genes over time.
- A defective gene that controls growth of the heart muscle
In people over age 60, HCM is likely to be caused by or related to high blood pressure.
HCM is usually most severe when it occurs in younger people, but it can occur at any age.
Other factors that may increase your chances of HCM include:
- Having a family member with HCM
- Being over age 60 and having hypertension
- Chest pain
- Fainting, particularly during exercise
- Lightheadedness, particularly following exercise
- Rapid heartbeat
- Shortness of breath or difficulty breathing
- General fatigue
- Tiring easily during exercise or activity
- Shortness of breath when lying down
These symptoms can be caused by some of the side effects of the condition, including heart arrhythmias. 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 ECG.
Many individuals with HCM live a normal, healthy life with few symptoms. However, HCM does increase the risk of sudden death.
Treatment focuses on controlling symptoms and preventing complications. Talk with your doctor about the best treatment plan for you. Treatment may include:
Medicines may be used to help maintain proper and regular heart function. These may include:
- Beta-blockers and calcium channel blockers
- Blood thinners
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 Septal Ablation
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.
Implantable Cardioverter Defibrillators (ICD)
This ICD is implanted if you are at increased risk for sudden death.
To help reduce your chances of HCM:
- Talk to your doctor about screening tests if you have a family history.
- Follow your treatment plan to manage chronic heart or other medical conditions.
American Heart Association http://www.heart.org
Cardiomyopathy Association http://www.cardiomyopathy.org
Canadian Cardiovascular Society http://www.ccs.ca
Heart and Stroke Foundation of Canada http://www.heartandstroke.ca
Cardiomyopathy in adults. American Heart Association website. Available at: http://www.heart.org/HEARTORG/Conditions/More/Cardiomyopathy/Cardiomyopathy%5FUCM%5F444459%5FSubHomePage.jsp. Accessed September 15, 2017.
Explore cardiomyopathy. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/cm. Updated June 22, 2016. Accessed September 15, 2017.
Hypertrophic cardiomyopathy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypertrophic-cardiomyopathy . Updated May 12, 2017. Accessed September 15, 2017.
What is HCM? St. Luke's Roosevelt Hospital Center website. Available at: http://www.hcmny.org/whatis/index.html. Accessed September 15, 2017.
- Reviewer: EBSCO Medical Review Board Michael J. Fucci, DO, FACC
- Review Date: 09/2018
- Update Date: 07/15/2020