What Causes Cardiomyopathy?

Cardiomyopathy can be acquired or inherited. "Acquired" means you aren't born with the disease, but you develop it due to another disease, condition, or factor.

"Inherited" means your parents passed the gene for the disease on to you. Researchers continue to look for the genetic links to cardiomyopathy. They also continue to explore how these links cause or contribute to the various types of cardiomyopathy.

Many times, the cause of cardiomyopathy isn't known. This is often the case when the disease occurs in children.

Dilated Cardiomyopathy

In more than half of the cases of dilated cardiomyopathy, the cause isn't known. As many as one-third of the people who have dilated cardiomyopathy inherit it from their parents.

Certain diseases, conditions, and substances also can cause the disease, such as:

• Coronary artery disease, heart attack, diabetes, thyroid disease, viral hepatitis, and HIV
• Infections, especially viral infections that inflame the heart muscle
• Alcohol, especially if you also have a poor diet
• Complications during the last month of pregnancy or within 5 months of birth
• Certain toxins, such as cobalt
• Certain drugs (such as cocaine and amphetamines) and two medicines used to treat cancer (doxorubicin and daunorubicin)

Hypertrophic Cardiomyopathy

Most cases of hypertrophic cardiomyopathy are inherited. It also can develop over time because of high blood pressure or aging.

Sometimes, other diseases, such as diabetes or thyroid disease, can cause hypertrophic cardiomyopathy. Sometimes the cause of hypertrophic cardiomyopathy isn't known.

Restrictive Cardiomyopathy

Certain diseases and conditions can cause restrictive cardiomyopathy, including:

• Hemochromatosis (HE-mo-kro-ma-TO-sis). This is a disease in which too much iron builds up in your body. The extra iron is toxic to the body and can damage the organs, including the heart.
• Sarcoidosis (sar-koy-DO-sis). This is a disease that causes inflammation (swelling). It can affect various organs in the body. The swelling is due to an abnormal immune response. This abnormal response causes tiny lumps of cells to form in the body's organs, including the heart.
• Amyloidosis (AM-i-loy-DO-sis). This is a disease in which abnormal proteins build up in the body's organs, including the heart.
• Connective tissue disorders.

Arrhythmogenic Right Ventricular Dysplasia

Researchers think that arrhythmogenic right ventricular dysplasia is an inherited disease.