Dilated cardiomyopathy is a disease of the heart muscle that usually starts in your heart's main pumping chamber (left ventricle). The ventricle stretches and thins (dilates) and can't pump blood as well as a healthy heart can. Over time, both ventricles may be affected. The term "cardiomyopathy" refers to diseases that affect the heart muscle itself.

Dilated cardiomyopathy might not cause symptoms, but for some people it can be life-threatening. It's a common cause of heart failure. Dilated cardiomyopathy can also lead to irregular heartbeats (arrhythmias), blood clots or sudden death.

The condition can affect anyone, including infants and children.

Signs and symptoms of dilated cardiomyopathy may include:

• Fatigue
• Shortness of breath (dyspnea) when you're active or lying down
• Reduced ability to exercise
• Swelling (edema) in your legs, ankles, feet and abdomen
• Chest pain or feelings of having a fast-beating, fluttering or pounding heart (palpitations)
• Extra or unusual sounds heard when your heart beats (heart murmurs), which your doctor may find during a physical examination

Some people with dilated cardiomyopathy don't have any signs or symptoms in the early stages of the disease.

When to see a doctor

If you are short of breath or have other symptoms of dilated cardiomyopathy, see your doctor as soon as possible. Call 911 or your local emergency number if you have chest pain that lasts more than a few minutes or have severe difficulty breathing.

If a family member has dilated cardiomyopathy, talk to your doctor. Early detection using genetic testing may benefit people with inherited forms of dilated cardiomyopathy who have no apparent signs or symptoms.

It may be difficult to determine the cause of dilated cardiomyopathy. The condition often runs in families (is inherited). However, many things can cause the left ventricle to dilate and weaken, including:

• Diabetes
• Obesity
• Heart rhythm problems (arrhythmias)
• High blood pressure (hypertension)
• Complications of late-stage pregnancy
• Excessive iron in your heart and other organs (hemochromatosis)
• Certain infections

Other possible causes of dilated cardiomyopathy include:

• Alcohol abuse
• Use of certain cancer medications
• Use of illegal drugs, such as cocaine or amphetamines
• Exposure to toxins, such as lead, mercury and cobalt

Risk factors for dilated cardiomyopathy include:

• Long-term high blood pressure
• Family history of dilated cardiomyopathy, heart failure or sudden cardiac arrest
• Inflammation of the heart muscle from immune system disorders, such as lupus
• Damage to the heart muscle from certain diseases, such as hemochromatosis
• Neuromuscular disorders, such as muscular dystrophy
• Long-term excessive alcohol or illegal drug use

Complications from dilated cardiomyopathy include:

• Heart failure. If you have dilated cardiomyopathy, your heart might not be able to supply your body with the blood it needs to work properly, leading to heart failure. Fluid can build up in the lungs, abdomen, legs, ankles and feet.
• Heart valve regurgitation. Enlargement of the left ventricle may make it harder for your heart valves to close, causing a backward flow of blood and making your heart pump less effectively.
• Heart rhythm problems. Changes in your heart's structure and changes in pressure on your heart's chambers can lead to the development of abnormal heart rhythms (arrhythmias).
• Sudden cardiac arrest. Dilated cardiomyopathy can cause your heart to suddenly stop beating.
• Blood clots (emboli). Pooling of blood in the left ventricle can lead to blood clots, which may enter the bloodstream and cut off the blood supply to vital organs. These blood clots can cause stroke, heart attack or damage to other organs. Arrhythmias can also cause blood clots.

Dilated cardiomyopathy often runs in families, and is not preventable. However, healthy lifestyle habits can help you prevent or reduce complications of dilated cardiomyopathy. If you have or are at risk for dilated cardiomyopathy:

• Don't smoke.
• Don't drink alcohol, or drink in moderation.
• Don't use cocaine or other illegal drugs.
• Eat a healthy diet that is low in salt (sodium).
• Maintain a healthy weight.
• Follow an exercise program recommended by your doctor.
• Get enough sleep and rest.
• Manage stress.

Your doctor will perform a physical exam and ask questions about your personal and family medical history. He or she will use a device called a stethoscope to listen to your heart and lungs. You may be referred to a heart specialist (cardiologist) for testing.

Tests

Tests your doctor might order include:

• Blood tests. These tests give your doctor information about your heart. They also may reveal if you have an infection, a metabolic disorder or toxins in your blood that can cause dilated cardiomyopathy.
• Chest X-ray. Your doctor may order a chest X-ray to check your heart and lungs for changes or problems in the heart's structure and size, and for fluid in or around your lungs.
• Electrocardiogram (ECG or EKG). An electrocardiogram records electrical signals as they travel through your heart. Your doctor can look for patterns that may be a sign of an arrhythmia or problem with the left ventricle. Your doctor may ask you to wear a portable ECG device (Holter monitor) to record your heart rhythm for a day or two.
• Echocardiogram. This is the main test for diagnosing dilated cardiomyopathy. Sound waves produce images of the heart, allowing your doctor to see whether your left ventricle is enlarged. An echocardiogram can also reveal how much blood is pumped out of the heart with each beat and whether blood is flowing in the right direction.
• Exercise stress test. During this test, you walk on a treadmill or ride a stationary bike while attached to an ECG. Exercise testing can help reveal the cause and severity of dilated cardiomyopathy. If you're unable to exercise, you may be given medication to mimic the effect of exercise on your heart.
• CT or MRI scan. These imaging tests can show the size and function of your heart's pumping chambers.
• Cardiac catheterization. During this procedure, a long thin tube (catheter) is inserted in a blood vessel, usually in your groin, and guided to your heart. Dye may flow through the catheter to help your coronary arteries appear more clearly on X-ray. During cardiac catheterization, your doctor can measure pressure in your heart and collect a sample of tissue to check for muscle damage (biopsy).
• Genetic screening or counseling. If your doctor can't identify the cause of dilated cardiomyopathy, he or she may suggest screening of other family members to see if the disease is inherited in your family.

If you have dilated cardiomyopathy, your doctor might recommend treatment for the underlying cause, if known. Treatment may help relieve symptoms, improve blood flow and prevent further damage to your heart.

Medications

Doctors usually treat dilated cardiomyopathy with a combination of medications. Depending on your symptoms, you might need two or more drugs.

Drugs that are used to treat heart failure and dilated cardiomyopathy include:

• Angiotensin-converting enzyme (ACE) inhibitors. This type of medicine widens blood vessels (vasodilator) to lower blood pressure, improve blood flow and decrease the heart's workload. ACE inhibitors may improve heart function.

  Side effects include a dry cough, low blood pressure, low white blood cell count, and kidney or liver problems. In rare cases, ACE inhibitors may cause certain areas of the tissues to swell (angioedema). If swelling occurs in the throat, it can be life-threatening.

• Angiotensin II receptor blockers (ARBs). These drugs may be an alternative for people who can't tolerate ACE inhibitors. Side effects include diarrhea, muscle cramps and dizziness.
• Sacubitril/valsartan (Entresto). This drug combines an ARB with another type of medicine to help your heart better pump blood to the rest of the body. It's approved for people with chronic heart failure who have heart weakness and enlargement.
• Beta blockers. This medication slows your heart rate and reduces blood pressure. It may prevent some of the harmful effects of stress hormones, which are substances made by your body that can worsen heart failure and trigger abnormal heart rhythms. Side effects of beta blockers include dizziness and low blood pressure.
• Diuretics. Often called water pills, diuretics remove excess fluid and salt from your body. The drugs also decrease fluid in your lungs, so you can breathe more easily.
• Digoxin (Lanoxin). This drug can strengthen your heart muscle contractions. It also tends to slow the heartbeat. Digoxin may reduce heart failure symptoms and improve your ability to be active.
• Ivabradine (Corlanor). This drug helps restore the heart's normal rhythm by slowing and regulating the heart rate.
• Blood-thinning medications (anticoagulants). Your doctor may prescribe these drugs to help prevent blood clots. Side effects include excessive bruising or bleeding.

Therapies

Devices

Implantable devices used to treat dilated cardiomyopathy include:

• Biventricular pacemaker. This device sends out electrical signals to control contractions between the heart's left and right ventricles.
• Implantable cardioverter-defibrillators (ICD). An ICD monitors your heart rhythm and delivers electrical shocks when needed to control abnormal, rapid heartbeats, including those that cause the heart to stop. An ICD can also function as a pacemaker.
• Left ventricular assist devices (LVAD). This mechanical device is implanted into the abdomen or chest and attached to a weakened heart to help it pump. An LVAD may be used as a long- or short-term therapy for people waiting for a heart transplant. They usually are considered after less invasive approaches are unsuccessful.

Surgery or other procedures

Heart transplant

Your doctor may recommend a heart transplant if medications and other treatments for dilated cardiomyopathy no longer work for you.

If you have dilated cardiomyopathy, these self-care strategies may help you manage your symptoms:

• Exercise. Talk to your doctor about what activities would be safe and beneficial for you. In general, competitive sports aren't recommended because they can increase the risk of the heart stopping and causing sudden death.
• Quit smoking. Your doctor can give you advice on what methods can help you stop smoking.
• Don't use illegal drugs or drink alcohol excessively. Using cocaine or other illegal drugs can strain your heart. Before you drink alcohol, ask your doctor for advice.
• Maintain a healthy weight. Extra weight makes your heart work harder. Lose weight if you're overweight or obese.
• Eat a heart-healthy diet. This includes eating whole grains and a variety of fruits and vegetables, and limiting salt, added sugar, and cholesterol, saturated fats and trans fats. Ask your doctor for a referral to a dietitian if you need help planning your diet.

If you think you may have dilated cardiomyopathy or are worried about your risk because of a family history, make an appointment with your family doctor. Your doctor may refer you to a cardiologist, if necessary.

Here's information to help you get ready for your appointment.

What you can do

• Be aware of any pre-appointment restrictions. When you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.
• Write down symptoms you're experiencing, including any that may seem unrelated to dilated cardiomyopathy.
• Write down key personal information, including major stresses or recent life changes and a family history of heart disease, stroke, high blood pressure or diabetes.
• List all medications, including vitamins and supplements you're taking.
• Take a family member or friend along, if possible. Someone who accompanies you may remember something that you missed or forgot.
• Be prepared to discuss your diet and exercise habits. If you don't already follow a diet or exercise routine, talk to your doctor about how to get started.
• Write down questions to ask your doctor.

Preparing a list of questions will help you make the most of your time with your doctor. For dilated cardiomyopathy, some basic questions include:

• What is likely causing my symptoms or condition?
• What are other possible causes?
• What tests will I need?
• What's the best treatment?
• What are the alternatives to the primary approach you're suggesting?
• How should I change my diet?
• What's an appropriate level of physical activity?
• How often should I be screened?
• Should I tell my family to be screened for dilated cardiomyopathy?
• I have other health conditions. How can I best manage them together?
• Are there restrictions that I need to follow?
• Should I see a specialist?
• Is there a generic alternative to the medicine you're prescribing?
• Are there brochures or other printed materials I can take with me? What websites do you recommend?

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

• When did your symptoms begin?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Do any of your blood relatives have dilated cardiomyopathy or other types of heart disease?