Hypertrophic Cardiomyopathy

Topic Overview

What is hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy (say "hy-per-TROH-fik kar-dee-oh-my-AWP-uh-thee") happens when the heart muscle grows too thick, so the heart gets bigger and its chambers get smaller. This may result in:

No symptoms or few symptoms. Many people have no symptoms and live a normal life with few problems.
The heart not getting enough blood and oxygen, which can cause chest pain.
A fast, slow, or uneven heartbeat (arrhythmia). In rare cases, this can cause sudden death.
The heart not pumping blood well or not relaxing between beats as it normally does. In rare cases, this can lead to heart failure.

See a picture of a normal heart and a heart with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy is the most common genetic heart disease. This means it runs in families. About 1 out of 500 adults have this condition.¹

It cannot be cured, but you can treat the symptoms.

What causes hypertrophic cardiomyopathy?

Certain genes cause the heart to grow more than it should. If you have family members with the disease, you are more likely to get it.

What are the symptoms?

If you have hypertrophic cardiomyopathy, you may:

Have no symptoms.
Feel tired and short of breath when you are active.
Have chest pain (angina). You may have a heavy, tight feeling in your chest. Chest pain is often brought on by exercise, when the heart has to work harder.
Feel dizzy or faint, often after you have been active.
Feel like your heart is pounding, racing, or beating unevenly (palpitations).

Call your doctor if:

You have a rapid or irregular heartbeat or fainting spells. You may have an arrhythmia, which makes sudden death more likely. People with hypertrophic cardiomyopathy are at a higher risk for sudden death than other people and can die at a young age.
You have symptoms that might be caused by heart failure, such as shortness of breath, being very tired, or swelling in your legs or ankles.

How is hypertrophic cardiomyopathy diagnosed?

Your doctor will ask you about any health problems you've had and about any family history of heart disease or early and sudden death. Your doctor will do a physical exam. You may need tests such as an electrocardiogram (ECG or EKG), chest X-ray, echocardiogram, or MRI.

Your doctor may refer you to a doctor who specializes in heart problems (cardiologist). Based on your symptoms, past health, and family history, the specialist can assess your risk for sudden death. People who are at high risk will need regular checkups.

If either of your parents or a brother or sister has the disease or died suddenly at a young age, you are at risk. Talk to your doctor about getting tests to check for the disease.

How is it treated?

Many people who have hypertrophic cardiomyopathy don't need treatment. Treatment depends on your symptoms and whether you have developed heart failure or abnormal heart rhythms.

You may take medicines to treat symptoms such as shortness of breath and chest pain.
An arrhythmia such as atrial fibrillation is treated with medicines to control the heart rate and rhythm and to prevent blood clots. Or you may get cardioversion, an electrical shock to return the heart to its normal rhythm.
Heart failure is treated with medicines and lifestyle changes, such as eating less salt. Surgery also can be an option.

If your doctor feels you are at high risk for sudden death from an arrhythmia, you may need an implantable cardioverter-defibrillator (ICD). An ICD is a small device like a pacemaker. It treats dangerous heart rhythms.

What else can you do for hypertrophic cardiomyopathy?

Many adults with this disease have full and long lives. You can help yourself by not smoking and by eating healthy foods.

Avoid strenuous activity and intense exercise, because they could lead to sudden death. Talk with your doctor about activity levels that are right for you.

Also talk to your doctor about how often you need checkups.

Frequently Asked Questions

Learning about hypertrophic cardiomyopathy:	Are there different types of hypertrophic cardiomyopathy? What are the symptoms?
Being diagnosed:	How is hypertrophic cardiomyopathy diagnosed?
Getting treatment:	How is it treated?
Living with hypertrophic cardiomyopathy:	What can I do to take care of myself?

Symptoms

Many people who have hypertrophic cardiomyopathy do not have symptoms. But if symptoms occur, at first they generally include:

Shortness of breath (dyspnea).
Chest pain or discomfort (angina).
Fainting or near-fainting (syncope), especially with exertion.
Heart palpitations, an uncomfortable awareness of the heart beating rapidly or irregularly.

Sudden death may occur from the onset of ventricular tachycardia (a type of rapid heart rate) or other dangerous arrhythmias. A genetic factor appears to influence which people with hypertrophic cardiomyopathy are more prone to sudden death. Other risk factors for sudden death include severe obstruction of the left ventricle, multiple fainting (syncope) episodes, recurring episodes of ventricular tachycardia, and an abnormal drop in blood pressure during exercise.

Although it can occur in any age group, sudden death is most shocking when it happens to young adults or athletes. While these tragic deaths are often given prominence in the media, sudden death is rare (1 or less out of 100 adults with hypertrophic cardiomyopathy each year).²

Complications of hypertrophic cardiomyopathy

Atrial fibrillation is a common complication of hypertrophic cardiomyopathy. This abnormal heart rhythm interferes with the normal pumping of the heart. It can cause blood clots to develop in the heart, which can break off and travel through the bloodstream (systemic embolism). This may cause a stroke, heart attack, or blocked blood flow to an arm or leg.

Heart failure may develop if the disease progresses. In heart failure, the heart's lower chambers are not able to pump blood effectively enough to meet the body's needs for oxygen and nutrients. Common symptoms include fluid buildup (edema) in the legs, ankles, and feet; shortness of breath while lying down or exercising; and increased urination at night.

Athlete's heart syndrome

People who exercise regularly and vigorously often develop changes in their heart muscle that can be confused for hypertrophic cardiomyopathy. In such athletes, the heart muscle grows to adapt to the extra demands from physical activities. This condition is called athlete's heart syndrome. But unlike hypertrophic cardiomyopathy, athlete's heart syndrome does not cause life-threatening heart rhythms and sudden death. It is a benign, or harmless, condition. When an athlete stops training, the heart returns to a normal size unlike those with hypertrophic cardiomyopathy, in which the heart remains enlarged.

Exams and Tests

Hypertrophic cardiomyopathy can be difficult to diagnose, because it may not always cause symptoms. The first step in diagnosing heart problems is a thorough medical history and physical exam.

Your doctor will ask you about any family history of hypertrophic cardiomyopathy or any heart disease. Your doctor will also want to know if any relatives died an early and sudden death. Sometimes when young people die of cardiac arrest from hypertrophic cardiomyopathy, the disorder is not discovered because autopsies are not always done.

During the physical exam, your doctor will listen to your heart with a stethoscope. If any extra or unusual heart sounds (gallops or murmurs) are heard, it may mean the structure of the heart is abnormal.

You will likely have one or more of the following tests to help your doctor diagnose and treat your condition.

Electrocardiogram

An electrocardiogram (ECG or EKG) measures the electrical activity as it moves through the heart during contraction and relaxation. An abnormal electrocardiogram may be the first sign of hypertrophic cardiomyopathy in people who do not have any symptoms.

Echocardiogram

An echocardiogram (echo) is a type of ultrasound exam that uses high-pitched sound waves to create an image of the heart, which is seen on a television screen. An echo is the main tool used to help doctors diagnose hypertrophic cardiomyopathy and find out how bad it is.

Echocardiography can be used to:

Estimate how well the lower left chamber of the heart (left ventricle) is able to fill when the heart expands and measure how much blood is pumped out as it contracts (ejection fraction).
Find out if the heart valves are functioning normally.
Measure overall heart size.
Find out if the heart muscle (myocardium), including the wall that separates the left and right chambers of the heart, is unusually thick.
Measure the degree that blood flow is reduced during contraction (systole) if the wall that separates the left and right chambers of the heart is abnormally thick.

Physical exam, electrocardiogram, and echocardiogram are the best ways to diagnose hypertrophic cardiomyopathy. People with a family history of sudden death, especially young athletes or those who are thinking about starting an exercise program, should talk to their doctors about being tested for hypertrophic cardiomyopathy. These tests may also help evaluate a person who faints during strenuous physical activity.

If you are considered to be low-risk, you will see your doctor about every 3 years, not as often as people thought to be high-risk. If your symptoms change or get worse, an echocardiogram will usually be done.

Exercise test

Your doctor may have you run on a treadmill or pedal a stationary bike while he or she looks at how well your heart and lungs are working. An exercise test can give the doctor (and you) an idea of how hard and how long you can exercise.

The results of an exercise test may show that you have a higher risk for serious health problems because of hypertrophic cardiomyopathy. Some doctors recommend an exercise test before beginning any treatment for hypertrophic cardiomyopathy.

Imaging tests

Chest X-ray

A chest X-ray produces a photographic image of the heart using rays of intense light energy that pass through the body and project an image on a film. An X-ray can show information about the heart's size and shape. In later stages of hypertrophic cardiomyopathy, an X-ray may reveal signs of pulmonary edema, which is fluid buildup in the lungs.

MRI (Magnetic Resonance Imaging)

An MRI (magnetic resonance imaging) produces pictures of the heart to check for problems. It might be done to help diagnose hypertrophic cardiomyopathy.

Cardiac catheterization (cardiac cath) or coronary angiography

During a cardiac catheterization or coronary angiogram, a long, thin tube (catheter) is threaded through an artery or vein in the arm or groin and into the heart to measure pressure in the heart chambers. Dye can be injected through the catheter to see whether the coronary arteries are blocked, how well the heart chambers are pumping, and whether heart valves are leaking.

Angiography may be done if the results of the echocardiogram are inadequate. Angiography may also be used to check if surgery would be an option for treatment of hypertrophic cardiomyopathy.

Genetic testing

Genetic testing can identify some genes that are related to this condition. Genetic tests are not commonly used to diagnose hypertrophic cardiomyopathy.

Genetic testing might be done for close relatives of people who have hypertrophic cardiomyopathy. The testing can help see if they carry a genetic change that raises their risk for getting the disease. An echocardiogram or electrocardiogram are more commonly done to check their hearts.

Treatment Overview

Initial treatment

Many people with hypertrophic cardiomyopathy do not need treatment. But in some cases, having a thickened heart muscle can cause problems. If symptoms develop, treatment is usually recommended. Medicines cannot cure hypertrophic cardiomyopathy, but they may be used to treat complications, including atrial fibrillation and heart failure. These medicines include:

Beta-blockers. Beta-blockers are often used to treat people who develop symptoms such as shortness of breath or chest pain. They lower blood pressure, slow heart rate, and improve blood flow, which helps decrease symptoms and improves your ability to exercise. They may even prevent or delay the progression of heart failure related to hypertrophic cardiomyopathy.
Calcium channel blockers. Calcium channel blockers are used to help relieve symptoms, especially chest pain. These medicines also slow heart rate and lower blood pressure.
Antiarrhythmic medicines . These medicines are used to control the heart rhythm. One example is disopyramide (Norpace). An antiarrhythmic medicine might be used if you also have atrial fibrillation.

Atrial fibrillation occurs in about 1 out of 4 people who have hypertrophic cardiomyopathy. In atrial fibrillation, abnormal electrical impulses cause the upper chambers of the heart (atria) to fibrillate, or quiver, resulting in irregular and rapid beating of the ventricles, the heart's main pump. For most people, this aspect of atrial fibrillation in itself is usually not life-threatening. But for people who have hypertrophic cardiomyopathy, atrial fibrillation can increase your risk for other abnormal heart rhythms that can be life-threatening. It also increases your risk for heart failure and stroke. For these reasons, most doctors aggressively treat atrial fibrillation in people who have hypertrophic cardiomyopathy. Aggressive treatment may include medicines to control the heart rate or rhythm, electrical cardioversion to return the heart to its normal rhythm, or catheter ablation or surgery to destroy heart tissue that is causing atrial fibrillation. For more information, see the topic Atrial Fibrillation.

Anticoagulants often are prescribed for people who have atrial fibrillation. Anticoagulants help protect against blood clots that develop in the heart. Blood clots can be dangerous because they may break loose and travel through the bloodstream (thromboembolism), which may cause a stroke, heart attack, or blocked blood flow to an arm or leg.

Most people who have hypertrophic cardiomyopathy should be assessed by a cardiologist to find out their risk for ventricular tachycardia, an abnormally fast heart rate that can result in sudden death. For those in a high-risk category, an implantable cardioverter-defibrillator (ICD) appears to be the most effective treatment for preventing sudden death.

Because of the risk of sudden death, it is important for people who have hypertrophic cardiomyopathy to avoid too much strenuous activity and intense exercise. Talk to your doctor about what level of exercise and what kinds of activities are safe. Prolonged activity in hot weather is not recommended, because dehydration can also make symptoms worse in people who have hypertrophic cardiomyopathy.

Ongoing treatment

It is important for people with high-risk hypertrophic cardiomyopathy to have frequent check-ups with their doctors. People who are low-risk may not see their doctors as often. But you may see the doctor more often if you have a change in your symptoms or your overall health. When symptoms appear or start to get worse, a check-up might include an echocardiogram (echo), electrocardiogram (ECG, EKG), or exercise test. Your doctor will talk about your symptoms and your health history. You may also talk about the health history of people in your family. These regular visits will help your doctor identify things that may put you at risk for sudden cardiac death and other serious medical conditions.

If symptoms develop, treatment is usually recommended. Medicines cannot cure hypertrophic cardiomyopathy, but they may be used to treat complications, including atrial fibrillation and heart failure. After medicines are started, most people need to take them for the rest of their lives.

Treatment if the condition gets worse

If you have serious heart rhythm problems or are at high risk for sudden death, your doctor might recommend an implantable cardioverter-defibrillator (ICD).

Medicines for heart failure may be used if hypertrophic cardiomyopathy progresses to that advanced state. For more information, see the topic Heart Failure.

A surgery called a myectomy or myomectomy may be advised for some people when medicines do not help relieve severe symptoms of heart failure (NYHA class III and IV) due to hypertrophic cardiomyopathy. In this surgery, a portion of overgrown heart muscle is removed. Often the excess muscle tissue is found in the septum, which divides the left and right lower heart chambers (ventricles). An overgrown septum can interfere with the function of the left ventricle and limit blood flow out of the heart. Most people who have this surgery recover well and end up with fewer symptoms. After surgery, physical activity is easier too.

Another option for people who have hypertrophic cardiomyopathy is nonsurgical septal reduction, also called alcohol septal ablation. When the area of the heart muscle that divides the right and left chambers (septum) becomes too thick, the lower left heart chamber (left ventricle) becomes obstructed, which hinders its ability to pump normally. The thickened septum is reduced in size by injecting alcohol into the coronary artery that supplies this area of the heart with blood. The alcohol destroys some of the heart muscle in the thickened septum. This reduces the obstruction and improves the left ventricle's pumping ability. Advantages of this procedure are that major surgery and lengthy recovery are avoided because the alcohol can be given through a catheter during a cardiac catheterization procedure. This procedure can help relieve symptoms. But it is a newer procedure, so the long-term effects are not yet known. Experts recommend that this complex procedure be done in a large medical center where the staff has substantial experience with it.

Home Treatment

Because of the risk of sudden death, it is important for people who have hypertrophic cardiomyopathy to avoid too much strenuous activity and intense exercise. Sudden death in people who have hypertrophic cardiomyopathy can occur during or just after strenuous physical activity. Talk to your doctor about what level of exercise and what kinds of activities are safe. Because dehydration can also make symptoms in people with hypertrophic cardiomyopathy worse, prolonged activity in hot weather is not recommended.

The following self-care is also important:

Be active at low aerobic levels to help keep your heart and body healthy. Ask your doctor about activities that are safe for you.
If you smoke, try to quit. Medicines and counseling can help you quit for good.
Stay well hydrated (unless you have heart failure or another medical condition and need to limit your fluid intake).

Follow your doctor's recommendations for regular exams to monitor your condition.

Because some people who have hypertrophic cardiomyopathy may be at increased risk for sudden death, it is a good idea for family members to learn CPR (cardiopulmonary resuscitation).

Other Places To Get Help

Organizations

American Heart Association (AHA)
7272 Greenville Avenue
Dallas, TX 75231
Phone:	1-800-AHA-USA1 (1-800-242-8721)
Web Address:	www.heart.org

Visit the American Heart Association (AHA) website for information on physical activity, diet, and various heart-related conditions. You can search for information on heart disease and stroke, share information with friends and family, and use tools to help you make heart-healthy goals and plans. Contact the AHA to find your nearest local or state AHA group. The AHA provides brochures and information about support groups and community programs, including Mended Hearts, a nationwide organization whose members visit people with heart problems and provide information and support.

National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105
Phone:	(301) 592-8573
Fax:	(240) 629-3246
TDD:	(240) 629-3255
Email:	nhlbiinfo@nhlbi.nih.gov
Web Address:	www.nhlbi.nih.gov

The U.S. National Heart, Lung, and Blood Institute (NHLBI) information center offers information and publications about preventing and treating: Diseases affecting the heart and circulation, such as heart attacks, high cholesterol, high blood pressure, peripheral artery disease, and heart problems present at birth (congenital heart diseases). Diseases that affect the lungs, such as asthma, chronic obstructive pulmonary disease (COPD), emphysema, sleep apnea, and pneumonia. Diseases that affect the blood, such as anemia, hemochromatosis, hemophilia, thalassemia, and von Willebrand disease.

Related Information

References

Citations

Ommen SR, et al. (2011). Hypertrophic cardiomyopathy. In V Fuster et al., eds., Hurst's The Heart, 13th ed., vol. 1, pp. 817–864. New York: McGraw-Hill.

McKenna WJ, Elliott PM (2007). Hypertrophic cardiomyopathy. In EJ Topol, ed., Textbook of Cardiovascular Medicine, 3rd ed., pp. 482–501. Philadelphia: Lippincott Williams and Wilkins.

Other Works Consulted

Fifer MA, Vlahakes GJ (2008). Management of symptoms in hypertrophic cardiomyopathy. Circulation, 117(3): 429–439.

Gersh BJ, et al. (2011). 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation, 124(24): e783–e831.

Ho CY (2012). Hypertrophic cardiomyopathy in 2012. Circulation, 125(11): 1432–1438.

Maron BJ (2012). Hypertrophic cardiomyopathy. In RO Bonow et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 9th ed., vol. 2, pp. 1582–1594. Philadelphia: Saunders.

McKenna WJ, Elliott PM (2007). Hypertrophic cardiomyopathy. In EJ Topol, ed., Textbook of Cardiovascular Medicine, 3rd ed., pp. 482–501. Philadelphia: Lippincott Williams and Wilkins.

Credits

By	Healthwise Staff
Primary Medical Reviewer	Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical Reviewer	Robert A. Kloner, MD, PhD - Cardiology
Last Revised	July 23, 2012