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From the Spring 2006 Issue

Learning Center

Cardiomyopathy: What You Need to Know

You often hear about heart disease. But did you know that one kind of heart disease — cardiomyopathy — affects the heart muscle itself? There are several types of cardiomyopathy. The two most common forms are dilated cardiomyopathy and hypertrophic cardiomyopathy.

People with cardiomyopathy often go on to develop more serious heart conditions:

• Dilated cardiomyopathy (DCM) can often progress into heart failure.
• Hypertrophic cardiomyopathy (HCM) can sometimes lead to rapid heart rhythms and even sudden cardiac death.

What Is Dilated Cardiomyopathy?

Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy. With DCM, the heart muscle gets larger, as the "dilated" in its name implies (Figure 1).

Figure 1

Dilated Cardiomyopathy

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To understand what happens to the heart with DCM, imagine that the heart muscle is like a rubber band. As that rubber band stretches over time, it eventually loses its "snap" or elasticity.

Likewise, as the heart muscle stretches and the heart gets larger, the heart muscle loses some of its ability to pump or contract. Over time, as heart failure develops, the heart becomes less able to pump blood to the body as strongly as it did before.

Often the cause of DCM in a patient cannot be found. But sometimes doctors find the cause to be coronary artery disease, a virus, or alcoholism. Sometimes DCM is inherited.

Most of the time a person with DCM has no symptoms until heart failure develops. Then the person notices heart failure symptoms: fatigue, shortness of breath, or tissue swelling — often in the legs and feet.

How Is DCM Treated?

Many of the treatments for dilated cardiomyopathy are the same as the treatments for heart failure:

• Lifestyle changes — Your doctor might suggest that you cut back on the salt (sodium) in your diet and get daily exercise.
• Medications — Beta blockers and ACE (angiotensin converting enzyme) inhibitors are two medications often used to treat DCM. If you have swelling, your doctor may also prescribe water pills (diuretics).
• Cardiac devices — If heart failure makes your heart pump in an uncoordinated way, you might receive an implantable cardiac resynchronization therapy (CRT) device. This device sends tiny amounts of electrical energy to your heart to help re-coordinate the pumping. If you are at risk for dangerous arrhythmias, you might also receive an implantable cardioverter defibrillator. The defibrillator can stop an arrhythmia before it causes sudden cardiac death.
• Surgery — Some patients may need surgery to repair a heart valve. Or, doctors may consider a heart transplant for patients with very severe symptoms.

What Is Hypertrophic Cardiomyopathy?

Hypertrophic cardiomyopathy is a thickening of part of the heart muscle. As the heart muscle thickens, it also becomes stiffer (Figure 2). In some cases the thicker muscle blocks part of the blood flow out of the heart. As a result, HCM can cause fast arrhythmias (abnormal heart rhythms) and sudden cardiac death.

Figure 2

Hypertrophic Cardiomyopathy

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In most cases, HCM is inherited from parents or caused by a problem that developed with a gene before birth. In either situation, people with HCM can pass the gene for HCM on to their children. In other cases, HCM can be caused by high blood pressure or aging.

Symptoms of HCM vary, but can include chest pain, dizziness, or passing out.

People of any age can have hypertrophic cardiomyopathy. For young people, unfortunately, HCM often causes sudden cardiac death before they even know they have HCM. In fact, hypertrophic cardiomyopathy is the most common cause of sudden cardiac death in people under age 30.1

If you have a family member with HCM, sudden cardiac death can be a serious risk. Talk to your doctor about being tested.

How Is HCM Treated?

Often people with HCM have mild symptoms, and many can expect to have a normal lifespan. But patients usually receive treatments if they have symptoms or are at risk of sudden cardiac death. Treatments include the following:

• Medications — Your doctor may order a beta blocker to help decrease your heart's stiffness.
• Surgery — Some patients may have surgery to remove part of the thickened heart muscle.
• Cardiac devices — People at high risk of sudden cardiac death might receive an implantable cardioverter defibrillator. The defibrillator is designed to stop a dangerous arrhythmia before it causes sudden cardiac death.

Get Treatment if Needed

Both dilated cardiomyopathy and hypertrophic cardiomyopathy can lead to more serious heart conditions — such as heart failure and sudden cardiac death.

Your doctor can tell you if you have DCM or are at risk for HCM. Knowing your risks is the first step toward getting treated. And the proper treatment can often help you live a longer, better life.

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Learn More

Non-ischemic Dilated Cardiomyopathy — Cleveland Clinic gives a detailed overview of DCM.

Dilated Cardiomyopathy — Provides an in-depth look at DCM. Also describes the type of DCM related to pregnancy, as well as the type caused by too much alcohol.

What is Hypertrophic Cardiomyopathy? — The Hypertrophic Cardiomyopathy Association provides an in-depth look at HCM, related research findings, and frequently asked questions.

Hypertrophic Cardiomyopathy — Briefly describes HCM, its effects, and its typical treatments.

1. Maron B. Hypertrophic Cardiomyopathy. Circulation. 2002;106:2419.