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Dilated cardiomyopathy

Definition

Dilated cardiomyopathy is a condition in which the heart becomes weakened and enlarged, and it cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems.

There are several different types of cardiomyopathy. Dilated cardiomyopathy is the most common form.

See also:

• Hypertrophic cardiomyopathy
• Ischemic cardiomyopathy
• Restrictive cardiomyopathy

Alternative Names

Cardiomyopathy - dilated

Causes, incidence, and risk factors

There are many causes of dilated cardiomyopathy. Some of these are:

• Alcohol (alcoholic cardiomyopathy) or cocaine abuse
• Atrial fibrillation, supraventricular tachycardia, or other heart rhythm problems in which the heart beats very fast for a long period of time (called Tachycardia-mediated cardiomyopathy)
• Autoimmune illnesses that involve the heart, such as systemic lupus erythematosus and rheumatoid arthritis
• Catecholamine excess from a tumor that releases catecholamines (pheochromocytoma)
• Coronary artery disease (See: Ischemic cardiomyopathy)
• Deficiencies of certain vitamins and minerals (thiamine, calcium, magnesium)
• End-stage kidney disease
• Family history of cardiomyopathy (some cardiomyopathies run in families and have a genetic component)
• Infections that involve the heart muscle, such as viruses, HIV infection, Chagas disease, and Lyme disease
• Inherited disorders such as muscular dystrophy
• Medications that can be toxic to the heart (such as some chemotherapy drugs used to treat cancer)
• Poorly controlled high blood pressure
• Pregnancy (See: Peripartum cardiomyopathy)
• Stress-induced cardiomyopathy
• Trace elements, such as lead, arsenic, or mercury

This condition can affect anyone at any age. However, it is most common in adult men.

The most common causes of dilated cardiomyopathy in children are:

• Heart (coronary) disease
• Myocarditis
• Some infections
• Unknown cause (idiopathic dilated cardiomyopathy)

Symptoms

Symptoms of heart failure are most common. Usually, they develop slowly over time. However, sometimes symptoms start very suddenly and are severe. Common symptoms are:

• Shortness of breath with activity or after lying down (or being asleep) for a while, or in infants while feeding
• Swelling of feet and ankles (in adults)
• Irregular or rapid pulse
• Fatigue, weakness, faintness
• Swelling of the abdomen (in adults)
• Loss of appetite
• Cough

Other symptoms may include:

• Chest pain
• Decreased alertness or concentration
• Failure to thrive (in children)
• Low urine production
• Need to urinate at night (in adults)
• Shock

Signs and tests

Cardiomyopathy is usually discovered when the doctor is examining and testing you for the cause of heart failure.

• Tapping over the heart with the fingers and feeling the area may indicate that the heart is enlarged.
• Listening to the chest with a stethoscope reveals lung crackles, heart murmur, or other abnormal sounds.
• The liver may be enlarged.
• Neck veins may be bulging.

A number of laboratory tests may be done to determine the cause:

• Antinuclear antibody (ANA), erythrocyte sedimentation rate (ESR), and other tests to diagnose autoimmune illnesses
• Antibody test to identify infections such as Lyme disease and HIV
• Serum TSH and T4 test to identify thyroid problems

Children will have:

• Poor growth
• Pale skin
• Difficulty feeding
• Weak pulses in the legs and arms

Heart enlargement, congestion of the lungs, decreased movement/functioning of the heart, or heart failure may show on these tests:

• Echocardiogram (ultrasound of the heart)
• Cardiac stress tests
• Cardiac catheterization and coronary angiography
• Chest CT scan or MRI of the heart
• Chest x-ray
• Nuclear heart scan (MUGA, RNV)

Other tests may include:

• ECG
• Heart biopsy

Lab tests vary depending on the suspected cause.

Treatment

When the cause of the dilated cardiomyopathy can be found, that condition is treated. For example, high blood pressure or coronary artery disease should be treated. If alcohol or cocaine use is the cause, your doctor will ask you to stop using them. Sometimes, no specific cause can be found, but the treatments listed below will still be used.

Attempts are also made to find a "trigger" that may have caused a sudden worsening in a patient's symptoms. Examples include not taking medication correctly, increasing salt or fluid intake, or drinking excess alcohol.

Treatment for cardiomyopathies focuses on treating heart failure. Drugs and treatments that may be used include:

• ACE inhibitors, such as captopril, enalapril, lisinopril, and ramipril
• Angiotensin receptor blockers (ARBs) such as losartan and candesartan
• Beta-blockers, such as carvedilol and metoprolol
• Diuretics, including thiazide, loop diuretics, and potassium-sparing diuretics
• Digitalis glycosides
• Drugs that dilate blood vessels (vasodilators)

See also: Heart failure

Some people may benefit from the following heart devices:

• Single or dual-chamber pacemaker
• Biventricular pacemaker
• Implantable cardioverter-defibrillator
• Left ventricular assist device (LVAD)

A low-salt diet may be prescribed for adults, and fluid may be restricted in some cases. You can usually continue your regular activities, if you are able.

You may be asked to monitor your body weight daily. Weight gain of 3 pounds or more over 1 or 2 days may indicate fluid buildup (in adults).

Avoid smoking and drinking alcohol, which may make the symptoms worse.

If the heart function remains poor, a heart transplant may be considered.

Support Groups

Expectations (prognosis)

The outcome varies. Some people remain in a stable condition for long periods of time, some continue to gradually get sicker, and others quickly get worse. Cardiomyopathy can only be corrected if the disease that caused it can be cured.

About one-third of children recover completely, one-third recover but continue to have some heart problems, and one-third die.

Complications

• Arrhythmias
• Congestive heart failure
• Pulmonary edema
• Side effects of medications, including:
  • Headache
  • Gastrointestinal upset
  • Light-headedness and fainting
  • Low blood pressure
  • Lupus reaction (a group of symptoms including a skin rash and arthritis)

Calling your health care provider

Call your health care provider if you have symptoms of cardiomyopathy.

If chest pain, palpitations, or faintness develop seek emergency medical treatment immediately.

Prevention

• Eat a well-balanced and nutritious diet
• Exercise to improve heart fitness
• Stop smoking
• Minimize alcohol consumption

References

Hare JM. The dilated, restrictive, and infiltrative cardiomyopathies. Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 64.

Wexler RK, Elton T, Pleister A, Feldman D. Cardiomyopathy: An overview. Am Fam Physician. 2009;79:778-784.

Bernstein D. Diseases of the myocardium. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 439.