Cardiomyopathy may be due to many reasons. For instance, in can be inherited or acquired. Inherited means that the genes have been passed on by the parents to the person in question, and even today, constant genetic research is going on to find out what causes this, to find out the effects of these links. However, as stated before, cardiomyopathy can be acquired – which means that a person is not born with the disease, rather it is developed through another factor, condition or a result of another disease – examples of some causes – alcoholism, thiamine deficiency, potassium deficiency, congenital heart defect, etc.

In the case of dilated cardiomyopathy, sometimes the cause is not known, but usually it is inherited from the parents. But other diseases, substances and conditions can cause dilated cardiomyopathy, like alcohol, poor diet, infections (especially viral infections that inflame the heart muscle), coronary artery disease, thyroid disease, heart attack, HIV, complications during the last month of pregnancy, and certain drugs.

Hypertrophic cardiomyopathy is also mostly inherited, but it can also be acquired due to high blood pressure, or through age. Thyroid disease can also cause this kind of cardiomyopathy.

Restrictive cardiomyopathy can be caused by hemochromatosis, sarcoidosis, amyloidosis, and connective tissue disorders.