The heart muscle may become inflamed in a condition called myocarditis,[27] most commonly caused by a viral infection[28] but sometimes caused by the body's own immune system.[29] Heart muscle can also be damaged by drugs such as alcohol, long standing high blood pressure or hypertension, or persistent abnormal heart racing.[30] Specific diseases of heart muscle called cardiomyopathies can cause heart muscle to become abnormally thick (hypertrophic cardiomyopathy),[31] abnormally large (dilated cardiomyopathy),[32] or abnormally stiff (restrictive cardiomyopathy).[33] Some of these conditions are caused by genetic mutations and can be inherited.[34]