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?
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:
- Severe coronary artery disease
- Thyroid disease
- Viral infections of the heart
- Heart valve abnormalities
- Drugs that are toxic (or cause damage) to the heart
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.
What Is the Treatment for DCM?
Treatment of dilated cardiomyopathy is aimed at decreasing the heart size and the substances in the bloodstream that enlarge the heart and ultimately lead to worsened symptoms:
Medications: To manage heart failure, most people improve by taking drugs, such as a beta-blocker, ACE inhibitor an ARB, and/or diuretics. If you have an arrhythmia (irregular heart beat), your doctor may give you a medication to control your heart rate or lessen the occurrence of arrhythmias. Blood thinners may be used to prevent blood clots from occurring.
Lifestyle changes: If you have heart failure, sodium should be restricted to 2,000-3,000 mg per day -- for the rest of your life. Your doctor may recommend aerobic exercise, but don't do heavy weight lifting.
What Surgeries Are Used to Treat DCM?
People with severe DCM may need one of the following surgeries:
- Cardiac resynchronization by biventricular pacemaker. For some people with DCM, stimulating both the right and left ventricles with this pacemaker improves the heart's ability to contract with more force, thereby improving symptoms and increasing the length of time you can exercise. This pacemaker also will help people with heart block or some bradycardias (slow heart rates).
- Implantable cardioverter defibrillators (ICD). ICDs are suggested for people at risk for life-threatening arrhythmias or sudden cardiac death. The ICD constantly monitors the heart rhythm. When it detects a very fast, abnormal heart rhythm, it ''shocks'' the heart muscle into returning to a normal rhythm.
- Surgery. Conventional surgeries for coronary artery disease or valvular disease may be recommended. Some people may be eligible for surgical repair of the left ventricle or placement of a cardiac assist device.
- Heart transplant
WebMD Medical Reference
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Cleveland Clinic Heart and Vascular Institute. The Cardiomyopathy Association. American Heart Association. Emedicine.
Reviewed by Michael F. Richman, MD, FCCP, FACS on February 29, 2012