Often, the cause of the cardiomyopathy is unknown. In some people, however, doctors are able to identify some contributing factors. Possible causes of cardiomyopathy include:

  • Genetic conditions
  • Long-term high blood pressure
  • Heart tissue damage from a previous heart attack
  • Chronic rapid heart rate
  • Heart valve problems
  • Metabolic disorders, such as obesity, thyroid disease or diabetes
  • Nutritional deficiencies of essential vitamins or minerals, such as thiamin (vitamin B-1)
  • Pregnancy complications
  • Drinking too much alcohol over many years
  • Use of cocaine, amphetamines or anabolic steroids
  • Use of some chemotherapy drugs and radiation to treat cancer
  • Certain infections, which may injure the heart and trigger cardiomyopathy
  • Iron buildup in your heart muscle (hemochromatosis)
  • A condition that causes inflammation and can cause lumps of cells to grow in the heart and other organs (sarcoidosis)
  • A disorder that causes the buildup of abnormal proteins (amyloidosis)
  • Connective tissue disorders

Types of cardiomyopathy include:

  • Dilated cardiomyopathy. This is the most common type of cardiomyopathy. In this disorder, the pumping ability of your heart's main pumping chamber — the left ventricle — becomes less forceful. The left ventricle becomes enlarged (dilated) and can't effectively pump blood out of the heart.

    Although this type can affect people of all ages, it occurs most often in middle-aged people and is more likely to affect men. Some people with dilated cardiomyopathy have a family history of the condition. In others, dilated cardiomyopathy may occur as a result of certain conditions such as coronary heart disease, infection, chemotherapy, or drug or alcohol use. The cause may also be unknown (idiopathic).

  • Hypertrophic cardiomyopathy. This type involves abnormal thickening of your heart muscle, particularly affecting the muscle of your heart's main pumping chamber (left ventricle). The thickened heart muscle can make it harder for the heart to pump blood.

    Hypertrophic cardiomyopathy can develop at any age, but the condition tends to be more severe if it becomes apparent during childhood. Most affected people have a family history of the disease, and some genetic mutations have been linked to hypertrophic cardiomyopathy.

  • Restrictive cardiomyopathy. The heart muscle in people with restrictive cardiomyopathy becomes rigid and less elastic, meaning the heart can't properly expand and fill with blood between heartbeats. While restrictive cardiomyopathy can occur at any age, it most often tends to affect older people. It's the least common type of cardiomyopathy and can occur for no known reason (idiopathic).

    The condition may also be caused by diseases elsewhere in the body that affect the heart, such as a disease in which iron builds up in the heart muscle (hemochromatosis), a disorder that causes the buildup of abnormal proteins (amyloidosis), a disease that causes inflammation and can cause lumps of cells to grow in the heart and other organs (sarcoidosis), connective tissue disorders, or a disorder that causes abnormal blood cells to damage the heart (eosinophilic heart disease).

  • Arrhythmogenic right ventricular dysplasia. In this rare type of cardiomyopathy, the muscle in the lower right heart chamber (right ventricle) is replaced by scar tissue. This can lead to heart rhythm problems. This condition is often caused by genetic mutations.
  • Other types of cardiomyopathy. Other types of cardiomyopathy (unclassified cardiomyopathies) exist, but they don't fit within the other types of cardiomyopathy.
Mar. 17, 2015

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