Cardiomyopathy may be caused by external factors or other non-genetic diseases. The most common cause of acquired cardiomyopathy is myocarditis, a viral infection that weakens the heart muscle. In such cases, a virus such as Coxsackie B causes the body's immune system to malfunction leading to inflammation of the heart muscle.
Children with cancer who undergo chemotherapy may develop cardiomyopathy. A class of drugs used to treat cancer called anthracyclines (doxorubicin and daunorubicin) can be toxic to the heart and cause heart muscle damage and problems with the heart’s pumping ability.
While we currently think of these cardiomyopathies as acquired, researchers are examining whether genetic factors may increase the risk of myocarditis or anthracycline-induced cardiotoxicity in some children.
Other acquired causes of secondary cardiomyopathy include: