Heart Disease Health Center

What is dilated cardiomyopathy?

Dilated cardiomyopathy is a serious condition that weakens your heart muscle and causes it to stretch, or dilate. When your heart muscle is weak, it can't pump out blood as well as it should, so more blood stays in your heart after each heartbeat. As more blood fills and stays in the heart, the heart muscle stretches even more and gets even weaker.

Most of the time, this leads to heart failure. Heart failure does not mean that your heart stops pumping. It means that your heart can't pump enough blood to meet your body's needs.

What causes dilated cardiomyopathy?

The most common type of dilated cardiomyopathy develops after a heart attack has damaged the heart muscle. But it can also be caused by many diseases or problems that may or may not be related to your heart. Sometimes the cause is not known.

Some of the things that can lead to dilated cardiomyopathy include:

• Coronary artery disease and heart attack.
• High blood pressure, which can put stress on the heart walls.
• Heart valve diseases, including aortic valve regurgitation and mitral valve regurgitation.
• Myocarditis, which is inflammation of the heart muscle. It is caused by a virus or an immune system problem.
• Drinking too much alcohol, using certain illegal drugs such as cocaine, or taking certain medicines such as chemotherapy.
• Being exposed to toxic metals, such as lead or mercury.
• Being pregnant. In rare cases, dilated cardiomyopathy develops toward the end of pregnancy or during the first 6 months after a woman gives birth. Experts don't know why this happens.

What are the symptoms?

You may not have any symptoms at first. Or you may have mild symptoms, such as feeling very tired or weak.

If your heart gets weaker, you will develop heart failure. When this happens, you will feel other symptoms, including:

• Shortness of breath, especially with activity.
• Tiredness.
• Trouble breathing when you lie down.
• Swelling in your legs.
• Chest pain.

You may get these symptoms slowly, over months or years. Or you may get them suddenly, such as after pregnancy or an illness caused by a virus.

Heart failure that suddenly gets worse is an emergency. Get medical help right away if:

• You have severe trouble breathing.
• You cough up pink, foamy mucus.
• You have a new irregular or rapid heartbeat.

When you have heart failure, keeping track of your symptoms every day is important. Call your doctor if:

• You have a sudden weight gain such as 3 lb (1.4 kg) or more in 2 to 3 days.
• Your ability to exercise changes.
• You have any change in your symptoms.

How is dilated cardiomyopathy diagnosed?

Your doctor will ask questions about your symptoms and past health. He or she will want to know about recent illnesses and about heart disease in your family. Your doctor will listen to your heart and lungs and check your legs for fluid buildup.