Hypertrophic cardiomyopathy (HCM) is a form of cardiomyopathy. The heart muscle thickens more than it should because of problems with the genes. The thick muscle can cause several probelms such as:

Making it harder for the heart to work. It causes strain on the rest of the heart.
Interrupting flow of blood out of the heart.
Put pressure on nearby heart valve, called mitral valve. This can make the valve leaky.
Change the rhythm of the heart. It can make the heart pump in a disorganized way. Can cause abnormal rhythms but this is rare.

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—the muscle is not large enough to block blood flow.

Normal Heart and Heart with Hypertrophic Cardiomyopathy

Causes

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
Infection

In people over age 60, HCM is likely to be caused by or related to high blood pressure.

Risk Factors

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

Symptoms

Symptoms include:

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.

Diagnosis

The doctor will ask about symptoms and past health. A physical exam will be done.

A blood test may be done to look for changes or possible causes. Amyloidosis, sarcoidosis, coronary artery disease, or valvular heart disease can cause a different type of cardiomyopathy.

A stress test may also be done to see how the heart works under pressure. Images of the heart may be taken with:

Electrical activity of the heart may need to be tracked. This can be done with an ECG that can be worn all day.

Treatment

Many people with HCM live a normal, healthy life with few symptoms. However, HCM does increase the risk of sudden death.

Treatment focuses on managing symptoms and preventing problems. Treatment may include:

Medicine

Medicines may be used to help the heart work better. These may include:

Beta-blockers and calcium channel blockers
Antiarrhythmics
Blood thinners

Surgery

Surgery may be needed to remove thickened part of the heart muscle. It may be done if the muscle is blocking too much blood flow from the heart.

Surgery may also be done to repair or replace the mitral valve if it is leaking.

Alcohol Septal Ablation

Alcohol is injected into the blood vessels that feed the enlarged heart. It will make part of the tissue shrink back. This should decrease blockage in the heart and improve blood flow out of the heart.

Implantable Cardioverter Defibrillators (ICD)

An ICD can help to control abnormal heart rhythms. It send an electrical impulse automatically when needed. It may be done if there is an increased risk for sudden death.

Prevention

Some chronic heart issues or medical conditions increase the risk of HCM. Following the care plan may help to decrease the risk of HCM developing.

RESOURCES:

American Heart Association
http://www.heart.org

Cardiomyopathy Association
http://www.cardiomyopathy.org

CANADIAN RESOURCES:

Canadian Cardiovascular Society
http://www.ccs.ca

Heart and Stroke Foundation of Canada
http://www.heartandstroke.com

References:

Cardiomyopathy in adults. American Heart Association website. Available at:
...(Click grey area to select URL)
Accessed September 15, 2020.

Explore cardiomyopathy. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health/health-topics/topics/cm. Accessed September 15, 2020.

Hypertrophic cardiomyopathy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypertrophic-cardiomyopathy. Accessed September 15, 2020.

What is HCM? St. Luke's Roosevelt Hospital Center website. Available at:
...(Click grey area to select URL)
Accessed September 15, 2020.

Last reviewed September 2020 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC
Last Updated: 8/14/2020

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