Dilated Cardiomyopathy

Overview

Dilated cardiomyopathy (DCM) is a disease of the heart muscle in which the heart's main pumping chamber, the left ventricle, becomes stretched, enlarged, and weakened. As the muscle thins and the chamber widens, the heart cannot squeeze as forcefully, so it pumps less blood with each beat.

DCM is one of the most common types of cardiomyopathy and a frequent cause of heart failure. Over time it can lead to fluid buildup, abnormal heart rhythms, and other complications. Some people have mild disease with few symptoms, while others develop significant heart failure. The condition has many possible causes, and treatment focuses on supporting the heart, managing symptoms, and treating the underlying cause when one is found.

Symptoms

Symptoms often develop gradually as the heart's pumping ability declines, and many reflect heart failure:

• Shortness of breath, with activity, when lying flat, or waking at night.
• Fatigue and reduced ability to exercise.
• Swelling in the legs, ankles, feet, or abdomen.
• Palpitations or an awareness of irregular heartbeats.
• Dizziness or fainting.
• A persistent cough or wheezing, sometimes from fluid in the lungs.

Some people have no symptoms early on. Severe shortness of breath, chest pain, fainting, or signs of a stroke require emergency care. DCM can also lead to blood clots, so sudden symptoms such as a swollen, painful leg or signs of a clot traveling to the lungs are also urgent.

Causes

Dilated cardiomyopathy has many possible causes, and in some people no cause is identified. Known contributors include:

• Genetic and inherited factors, as DCM can run in families.
• Viral infections that inflame the heart muscle (myocarditis).
• Long-term heavy alcohol use and certain recreational drugs.
• Coronary artery disease and prior heart attacks, which damage heart muscle.
• Uncontrolled high blood pressure over time.
• Certain medications and toxins, including some chemotherapy drugs.
• Pregnancy-related cardiomyopathy, which can develop late in pregnancy or after delivery.
• Thyroid disease and other metabolic conditions.

Risk Factors

Factors that increase the risk of developing dilated cardiomyopathy include:

• A family history of cardiomyopathy or heart failure.
• Long-term heavy alcohol use or substance use.
• High blood pressure or coronary artery disease.
• Previous heart muscle inflammation from a viral infection.
• Certain cancer treatments.
• Pregnancy, in the case of peripartum cardiomyopathy.

Diagnosis

Diagnosis combines a clinical evaluation with tests of heart structure and function:

• Echocardiogram, the main test, which shows the size of the heart chambers and how well the heart pumps.
• Electrocardiogram (ECG) to check the heart's electrical activity and rhythm.
• Chest X-ray, which may show an enlarged heart or fluid in the lungs.
• Blood tests, including markers of heart strain and tests for underlying causes such as thyroid problems.
• Cardiac MRI for detailed images of the heart muscle.
• Additional tests, such as monitoring of heart rhythm, coronary evaluation, and sometimes genetic testing or family screening.

Treatment

Treatment aims to improve the heart's function, relieve symptoms, prevent complications, and address any underlying cause. Approaches include:

• Medications commonly used for heart failure, which help the heart pump more effectively, reduce strain, control blood pressure and rhythm, and remove excess fluid.
• Treating the underlying cause, such as stopping alcohol, managing blood pressure, or treating an infection or thyroid problem.
• Blood thinners in some cases to reduce the risk of clots.
• Devices, including implantable defibrillators to protect against dangerous rhythms and specialized pacemakers to coordinate the heartbeat.
• Lifestyle measures, such as limiting salt and fluids as advised, staying active within recommended limits, and avoiding alcohol.
• Advanced therapies, including mechanical support devices or heart transplant, for severe cases that do not respond to other treatments.

Prevention

Not all cases can be prevented, especially genetic ones, but you can lower the risk of some causes and slow progression:

• Limit alcohol and avoid recreational drugs that harm the heart.
• Manage high blood pressure, diabetes, and cholesterol.
• Treat infections promptly and follow up if you have had heart muscle inflammation.
• Attend follow-up appointments and take prescribed medications.
• If DCM runs in your family, talk with your doctor about screening.

When to See a Doctor

See a healthcare provider if you have shortness of breath, unusual fatigue, swelling in your legs or abdomen, palpitations, or fainting, or if cardiomyopathy or heart failure runs in your family.

Seek emergency care or call emergency services for severe shortness of breath, chest pain, fainting, a very rapid or irregular heartbeat with lightheadedness, or signs of a stroke such as face drooping, arm weakness, or slurred speech. A swollen, painful leg or sudden chest pain with breathlessness may indicate a blood clot and also needs urgent care.

Related Topics

Frequently Asked Questions

References

1. American Heart Association.
2. Mayo Clinic. Dilated cardiomyopathy.
3. National Heart, Lung, and Blood Institute (NHLBI).
4. MedlinePlus, U.S. National Library of Medicine.