Hypertrophic Cardiomyopathy

Overview

What is hypertrophic cardiomyopathy (HCM)?

Hypertrophic cardiomyopathy (HCM) is a complex type of heart disease that affects your heart muscle. It can cause:

  • Thickening of your heart muscle (especially the ventricles or lower heart chambers).
  • Left ventricular stiffness.
  • Mitral valve changes.
  • Cellular changes.

How does hypertrophic cardiomyopathy (HCM) affect my body?

Thickening of the heart muscle (myocardium)

This occurs most commonly at your septum. The septum is the muscular wall that separates the left and right sides of your heart. Problems happen when the septum between your heart’s lower chambers (or ventricles) is thickened.

The thickened septum may cause a narrowing that can block or reduce the blood flow from the left ventricle to the aorta — a condition called outflow tract obstruction. The ventricles must pump harder to overcome the narrowing or blockage. This type of hypertrophic cardiomyopathy may be called hypertrophic obstructive cardiomyopathy (HOCM).

HCM also may cause thickening in other parts of your heart muscle, such as the bottom of your heart (called the apex), right ventricle or throughout your entire left ventricle. In these cases, it’s called hypertrophic nonobstructive cardiomyopathy. Although this type reduces the amount of blood your ventricle can handle, it doesn’t keep blood from moving.

Stiffness in the left ventricle

This occurs as a result of cellular changes that happen in your heart muscle when it thickens. Your left ventricle can’t relax normally and fill with blood. Since there’s less blood at the end of filling, there’s less oxygen-rich blood pumped to your organs and muscles. The stiffness in your left ventricle causes pressure to increase inside your heart and may lead to symptoms such as:

Mitral valve changes

When your left ventricular outflow tract becomes narrow, your mitral valve doesn’t work properly. This blocks outflow (obstruction) and increases pressure in your left ventricle.

The blockage (obstruction) is the result of your mitral valve striking your septum. When this occurs, your mitral valve frequently leaks, causing the blood to go back into your left atrium.

Cellular changes (changes in the cells of the heart muscle)

Through a microscope, heart muscle cells look disorganized and irregular (disarray) instead of being organized and parallel. This disarray may cause changes in the electrical signals traveling through the lower chambers of your heart and lead to a type of abnormal heart rhythm called ventricular arrhythmia.

How common is hypertrophic cardiomyopathy (HCM)?

Hypertrophic cardiomyopathy affects an estimated 600,000 to 1.5 million Americans or 1 in 500 people. It’s more common than multiple sclerosis, which affects 1 in 700 people.

How old are people when they get hypertrophic cardiomyopathy (HCM)?

This heart problem often shows up during the teen years, but it can start at other ages.

Can I get pregnant if I have hypertrophic cardiomyopathy (HCM)?

Although pregnant people with hypertrophic cardiomyopathy may need specialized care, such as echocardiography, most can support pregnancy and have a vaginal delivery. If you’re considering becoming pregnant, discuss your risks with your healthcare provider. Your provider can tell you which medicines for hypertrophic cardiomyopathy you can keep taking during your pregnancy. You may also be able to get a pacemaker or an implantable cardioverter defibrillator (ICD) if you need one during pregnancy.

Symptoms and Causes

What causes hypertrophic cardiomyopathy (HCM)?

There are several potential causes of hypertrophic cardiomyopathy, including:

  • Genetics. You can inherit hypertrophic cardiomyopathy from your parents and pass it on to your children. This means something is wrong with a gene that codes the characteristics of the heart muscle. There are many genes that can cause hypertrophic cardiomyopathy. When a gene defect is present, the type of hypertrophic cardiomyopathy that develops varies greatly within the family. Some people who have the hypertrophic cardiomyopathy gene may never develop the disease.
  • High blood pressure.
  • Aging.
  • Sometimes the cause of hypertrophic cardiomyopathy is unknown.

What are the symptoms of hypertrophic cardiomyopathy (HCM)?

People with hypertrophic cardiomyopathy may have a variety of symptoms or none at all. Common symptoms of hypertrophic cardiomyopathy include:

  • Chest pain. This usually happens with exercise or physical activity, but also may occur with rest or after meals.
  • Difficulty breathing (shortness of breath) and fatigue, especially with exertion. These symptoms are more common in adults with hypertrophic cardiomyopathy. Increased pressure in the left atrium and lungs is the cause.
  • Fainting or passing out (syncope). Irregular heart rhythms or abnormal responses of your blood vessels during exercise may cause fainting, or no cause may be found.
  • Feeling like your heart’s beating too fast or a fluttering in the chest (palpitations).
  • Abnormal heartbeats (arrhythmias) such as atrial fibrillation or ventricular tachycardia (both of which give you a fast heartbeat) may cause palpitations. About 25% of people with hypertrophic cardiomyopathy have atrial fibrillation, which increases the risk for blood clots and heart failure.
  • Swelling in the lower part of your body or in neck veins.

What conditions are associated with hypertrophic cardiomyopathy (HCM)?

The majority of people with hypertrophic cardiomyopathy live a normal life and don’t experience health-related problems. They may not even need to take medicine for their condition. However, your healthcare provider may tell you not to do strenuous exercise, even if you don’t have symptoms.

Other people with hypertrophic cardiomyopathy may develop heart conditions that shorten life or decrease their quality of life, including:

Sudden cardiac arrest and sudden cardiac death

Sudden cardiac arrest is a sudden loss of heart function caused by a dangerously fast heartbeat (ventricular tachycardia). If this happens, people need emergency treatments — including CPR and defibrillation — as soon as symptoms start. If people don’t get the treatments they need, sudden cardiac death can occur.

Most people with hypertrophic cardiomyopathy have a low risk for sudden cardiac death. However, hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in people under age 35. Hypertrophic cardiomyopathy may be best known for its role in cardiac arrest and death in some young professional athletes.

Heart failure

If you have heart failure, it doesn’t mean your heart has “failed” or stopped working. It means your heart doesn’t pump as well as it should. Symptoms of heart failure include:

  • Difficulty breathing (shortness of breath).
  • Feeling tired (fatigue) when you’re active.
  • Swelling in your ankles, legs and abdomen.
  • Need to urinate while resting at night.
  • Dizziness, confusion, difficulty concentrating, fainting.
  • Feeling that your heart is beating too fast (palpitations).
  • A dry, hacking cough.
  • A full (bloated) or hard stomach, loss of appetite, or upset stomach.

Diagnosis and Tests

How is hypertrophic cardiomyopathy (HCM) diagnosed?

The diagnosis of HCM is based on:

  • Medical history. Your healthcare provider will ask you questions about your symptoms and family history.
  • Physical exam. Your provider will listen to your heart and lungs. People with hypertrophic obstructive cardiomyopathy (HOCM) may have a heart murmur.
  • Tests. An echocardiogram is the most common test used to diagnose hypertrophic cardiomyopathy, as this test will usually show the thickening of your heart walls.

Other tests may include:

Management and Treatment

What treatments are there for hypertrophic cardiomyopathy (HCM)?

Your healthcare provider will base their recommendations for treatment on the following:

  • Whether you have narrowing in the path that blood travels as it leaves your heart (the outflow tract).
  • How your heart is functioning.
  • Your symptoms.
  • Your age and activity level.
  • If you have arrhythmias.

The goal of your treatment is to minimize or prevent symptoms and reduce the risk of complications, such as heart failure and sudden cardiac death.

Treatment can include:

  • Risk identification and regular follow-up.
  • Lifestyle changes.
  • Medications.
  • Procedures.

What type of screening is used to check for hypertrophic cardiomyopathy (HCM)?

Hypertrophic cardiomyopathy (HCM) is a medical condition that may be passed on from generation to generation. It’s important for you or your family members to have screening if you have a parent, sibling or child (first-degree relative) with the condition.

The first step is to have an electrocardiogram (ECG) and echocardiogram (echo) to check your heart. If the test results show signs of hypertrophic cardiomyopathy, you’ll need to see a medical doctor who specializes in the condition (cardiologist).

It’s possible to have normal test results even if hypertrophic cardiomyopathy runs in your family. In this case, you should have a follow-up echo and EKG every three years until you're 30 years old, and then every five years after that.

Most people with hypertrophic cardiomyopathy have a low risk for sudden cardiac death. However, it’s important to know if you’re among the small number of people with hypertrophic cardiomyopathy who do have a higher risk for sudden cardiac death. Your healthcare provider can help identify ways to reduce your risk.

People with hypertrophic cardiomyopathy who have a higher risk for sudden cardiac death include:

  • People who have a family history of sudden cardiac death.
  • Young people who have fainted (syncope) several times.
  • People who experience an abnormal blood pressure response with exercise.
  • People who have a history of an abnormally fast heart rate (arrhythmia).
  • People with severe symptoms and poor heart function.

Ask your healthcare provider about your personal risks. If you have two or more risk factors for sudden death, your provider may prescribe preventive treatments such as antiarrhythmic medications or an implantable cardioverter defibrillator (ICD) to reduce your risk.

What medications are used to manage hypertrophic cardiomyopathy (HCM)?

Healthcare providers often prescribe medications to treat your symptoms and prevent further complications. Medications such as beta blockers and calcium channel blockers relax the heart muscle, allowing it to fill better and pump more effectively. Other medications can help control your heart rate or decrease the occurrence of arrhythmias.

You may be told to avoid certain medications, such as nitrates (because they lower blood pressure) or digoxin (because it increases the force of the heart’s contraction).

You may need to take antibiotic medications and take other precautions to reduce the risk of bacterial endocarditis, a potentially life-threatening condition.

What procedures are used to treat hypertrophic cardiomyopathy (HCM)?

Procedures for the treatment of hypertrophic obstructive cardiomyopathy include:

Septal myectomy

During a septal myectomy, your surgeon removes a small amount of your thickened septal wall to widen the path your blood takes (outflow tract) from your left ventricle to your aorta. Your healthcare provider may consider a myectomy if medications aren’t working. This surgical procedure frequently eliminates the mitral valve problem.

Ethanol ablation

This procedure, also called septal ablation, is reserved for people who can’t have a septal myectomy. During this procedure, your healthcare provider locates the small coronary artery that supplies blood flow to the upper part of your septum. They insert a balloon catheter into the artery and then inflate the catheter. Then they inject a contrast agent to locate the thickened septal wall that narrows the passageway from your left ventricle to your aorta.

When your provider locates the bulge, they inject a tiny amount of pure alcohol through the catheter. The alcohol kills the cells on contact, making your septum shrink back to a more normal size over the following months. This widens the passage for blood flow.

Implantable cardioverter defibrillator (ICD)

ICDs can help people at risk for life-threatening arrhythmias or sudden cardiac death. The ICD is a small device placed just under your skin and is connected to wire leads that are threaded through the vein to your heart. An ICD constantly monitors your heart rhythm. When it detects a very fast, abnormal heart rhythm, it delivers energy (a small but powerful shock) to your heart muscle to make your heart beat in a normal rhythm again. Your provider will tell you if an ICD is a good treatment for you.

Heart failure management

There are several ways to manage heart failure, from making lifestyle changes to medications that relieve symptoms or help the muscle in your heart to work the way it should.

How can I improve my quality of life with hypertrophic cardiomyopathy (HCM)?

Whether you have symptoms or not, if you’re diagnosed with hypertrophic cardiomyopathy or it runs in your family, there are changes you can make to optimize your heart health.

  • Limit fluid and salt (sodium) intake. You may need to limit how much fluid and salt you drink and eat if you have heart failure symptoms. Ask your healthcare provider for specific guidelines about your diet, including information about alcoholic beverages and things that have caffeine.
  • Exercise with care. Your provider will discuss exercise guidelines with you. Most people with hypertrophic cardiomyopathy are able to do noncompetitive aerobic activities. Healthcare providers don’t recommend heavy weight lifting and many high-intensity sports.
  • Make regular follow-up appointments. If you have hypertrophic cardiomyopathy, you should follow up regularly with your cardiologist to monitor your condition.
  • Reduce your risk of infection. If you have hypertrophic cardiomyopathy, your healthcare provider may recommend that you take steps to reduce your risk of developing infective endocarditis.

How can I reduce my risk of developing infective endocarditis?

People with hypertrophic cardiomyopathy are at increased risk of developing bacterial or infective endocarditis.

Bacterial or infective endocarditis is an infection of your heart valves or your heart’s inner lining (endocardium). It happens when germs (especially bacteria, but occasionally fungi and other microbes) enter your bloodstream and attack the lining of your heart or your heart valves. Bacterial endocarditis causes growths or holes on your valves or scarring of your valve tissue, most often resulting in a leaky heart valve. Without treatment, bacterial endocarditis can be a fatal disease.

You can take these steps to reduce your risk:

Take good care of your teeth and gums by seeking professional dental care every six months, regularly brushing and flossing your teeth, and making sure dentures fit right.

Call your healthcare provider if you have symptoms of an infection, including:

  • A fever over 100 degrees F, sweats or chills.
  • Skin rash.
  • Pain, tenderness, redness or swelling.
  • A wound or cut that won’t heal, or a red, warm or draining wound.
  • Sore throat, scratchy throat or pain when swallowing.
  • Sinus drainage, nasal congestion, headaches or tenderness along upper cheekbones.
  • Persistent dry or moist cough that lasts more than two days.
  • White patches in your mouth or on your tongue.
  • Nausea, vomiting or diarrhea.

Don’t wait to seek treatment. Colds and the flu do not cause endocarditis. But infections, which may have the same symptoms, can cause endocarditis. To be safe, call your healthcare provider.

Take preventive antibiotics before certain medical and dental procedures. Please talk to your healthcare provider about the type and amount of antibiotics you should take, and for what procedures you should take them.

Carry a bacterial endocarditis identification card, which is available from the American Heart Association.

A note from Cleveland Clinic:

Most people with hypertrophic cardiomyopathy (HCM) lead normal lives, but several treatments are available for people who develop symptoms or are at risk for serious problems. Your outlook (prognosis) depends on how well your heart muscle is working, your symptoms, and how well you respond to and follow your treatment plan. Ask your healthcare provider about your risk and the steps you can take to improve your quality of life and prevent infection. If you’re diagnosed with hypertrophic cardiomyopathy and develop symptoms or are worried about an infection, reach out to your healthcare provider right away.

Last reviewed by a Cleveland Clinic medical professional on 03/18/2022.

References

  • Desai MY, Bhonsale A, Smedira NG. Predictors of Long Term Outcomes in Symptomatic Hypertrophic Obstructive Cardiomyopathy Patients Undergoing Surgical Relief of Left Ventricular Outflow Tract Obstruction. (http://www.ncbi.nlm.nih.gov/pubmed/23770748) Circulation. 2013;128(3):209-16. Accessed 3/18/2022.
  • Aljaroudi WA, Desai MY, Alraies MC. Relationship between baseline resting diastolic function and exercise capacity in patients with hypertrophic cardiomyopathy undergoing treadmill stress echocardiography: a cohort study. (http://www.ncbi.nlm.nih.gov/pubmed/23242244) BMJ Open. 2012;12:2(6). Accessed 3/18/2022.
  • Cavalcante JL, Barboza JS, Lever HM. Diversity of mitral valve abnormalities in obstructive hypertrophic cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/22687594) Prog Cardiovasc Dis. 2012;54(6):517-22. Accessed 3/18/2022.
  • Huff CM, Turer AT, Wang A. Correlations between physician-perceived functional status, patient-perceived health status, and cardiopulmonary exercise results in hypertrophic cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/22544415) Qual Life Res. 2013;22(3):647-52. Accessed 3/18/2022.
  • American Heart Association. Hypertrophic cardiomyopathy (HCM). (https://www.heart.org/en/health-topics/cardiomyopathy/what-is-cardiomyopathy-in-adults/hypertrophic-cardiomyopathy) Accessed 3/18/2022.
  • Marian AJ, Braunwald E. Hypertrophic Cardiomyopathy. (https://www.ahajournals.org/doi/10.1161/CIRCRESAHA.117.311059) Circulation Research. 2017;121:7:749-770. Accessed 3/18/2022.
  • Saberi S. Hypertrophic Cardiomyopathy in Pregnancy. (https://pubmed.ncbi.nlm.nih.gov/33222809/) Cardiology Clinics. 2021;39:1:143-150. Accessed 3/18/2022.
  • National Heart, Lung and Blood Institute. Atrial Fibrillation. (https://www.nhlbi.nih.gov/health-topics/atrial-fibrillation) Accessed 3/18/2022.

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