Causes

Often the cause of the cardiomyopathy is unknown. In some people, however, it's the result of another condition (acquired) or passed on from a parent (inherited).

Certain health conditions or behaviors that can lead to acquired cardiomyopathy include:

• Long-term high blood pressure
• Heart tissue damage from a heart attack
• Long-term rapid heart rate
• Heart valve problems
• COVID-19 infection
• Certain infections, especially those that cause inflammation of the heart
• Metabolic disorders, such as obesity, thyroid disease or diabetes
• Lack of essential vitamins or minerals in your diet, such as thiamin (vitamin B-1)
• Pregnancy complications
• Iron buildup in your heart muscle (hemochromatosis)
• The growth of tiny lumps of inflammatory cells (granulomas) in any part of your body, including your heart and lungs (sarcoidosis)
• The buildup of abnormal proteins in the organs (amyloidosis)
• Connective tissue disorders
• Drinking too much alcohol over many years
• Use of cocaine, amphetamines or anabolic steroids
• Use of some chemotherapy drugs and radiation to treat cancer

Types of cardiomyopathy include:

• Dilated cardiomyopathy. In this type of cardiomyopathy, the pumping ability of your heart's main pumping chamber — 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. The most common cause is coronary artery disease or heart attack. However, it can also be caused by genetic defects.

• Hypertrophic cardiomyopathy. This type involves abnormal thickening of your heart muscle, which makes it harder for the heart to work. It mostly affects the muscle of your heart's main pumping chamber (left ventricle).

  Hypertrophic cardiomyopathy can develop at any age, but the condition tends to be more severe if it occurs during childhood. Most people with this type of cardiomyopathy have a family history of the disease. Some genetic mutations have been linked to hypertrophic cardiomyopathy.

• Restrictive cardiomyopathy. In this type, the heart muscle becomes stiff and less flexible, so it can't expand and fill with blood between heartbeats. This least common type of cardiomyopathy can occur at any age, but it most often affects older people.

  Restrictive cardiomyopathy can occur for no known reason (idiopathic), or it can by caused by a disease elsewhere in the body that affects the heart, such as amyloidosis.

• 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, which can lead to heart rhythm problems. It's often caused by genetic mutations.
• Unclassified cardiomyopathy. Other types of cardiomyopathy fall into this category.