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Heart Disease Health Center

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Heart Disease and Dilated Cardiomyopathy

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What Is Dilated Cardiomyopathy?

Dilated cardiomyopathy (DCM) is a condition in which the heart's ability to pump blood is decreased because the heart's main pumping chamber, the left ventricle, is enlarged and weakened. In some cases, it prevents the heart from relaxing and filling with blood as it should. Over time, it can affect the other heart chambers.

What Are the Symptoms of DCM?

Many people with dilated cardiomyopathy have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which may progress and worsen as heart function worsens.

Symptoms of DCM can occur at any age and may include:

  • Heart failure symptoms (shortness of breath and fatigue).
  • Swelling of the lower extremities.
  • Fatigue (feeling overly tired).
  • Weight gain.
  • Fainting (caused by conditions such as irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found).
  • Palpitations (fluttering in the chest due to abnormal heart rhythms).
  • Dizziness or lightheadedness.
  • Blood clots can form in the dilated left ventricle as a result of pooling of the blood. If a blood clot breaks off, it can lodge in an artery and disrupt blood flow to the brain, causing stroke. A clot can also block blood flow to the organs in the abdomen or legs.
  • Chest pain or pressure.
  • Sudden death.

What Causes DCM?

DCM can be inherited, but it is primarily caused by a variety of other factors, including:

It can also occur in women after childbirth (postpartum cardiomyopathy).

How Is DCM Diagnosed?

DCM is diagnosed based on medical history (your symptoms and family history), physical exam, blood tests, electrocardiogram (ECG or EKG), chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, and MRI.

Another test rarely done to determine the cause of a cardiomyopathy is a myocardial biopsy, or heart biopsy, where a tissue sample is taken from the heart and examined under a microsope to determine the cause of the symptoms.

If you have a relative with dilated cardiomyopathy, ask your doctor if you should be screened for the condition. Genetic testing may also be available to identify abnormal genes.

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