Causes
Although in many cases no cause (etiology) is apparent, dilated cardiomyopathy is probably the result of damage to the myocardium produced by a variety of toxic, metabolic, or infectious agents. It may be due to fibrous change of the myocardium from a previous myocardial infarction. Or, it may be the late sequelae of acute viral myocarditis, such as with Coxsackie B virus and other enteroviruses, possibly mediated through an immunologic mechanism. Autoimmune mechanisms are also suggested as a cause for dilated cardiomyopathy.
It is important to take geography into account when considering aetiologies of any condition. In Latin America, Chagas disease due to Trypanosoma cruzi is the most common infectious cause of dilated cardiomyopathy
Dilated cardiomyopathy can also be caused by alcohol abuse (Alcoholic cardiomyopathy), or other toxic exposure, although the cause-and-effect relationship with alcohol alone is debated. Nonalcoholic toxic insults include administration of certain chemotherapeutic agents, particularly doxorubicin (Adriamycin), and cobalt.
Other potential causes include thyroid disease, stimulant use, and chronic uncontrolled tachycardia. Many cases of dilated cardiomyopathy are described as idiopathic — meaning that the cause is unknown.
Recent studies have shown that those subjects who have an extremely high occurrence (several thousands a day) of premature ventricular contractions (extrasystole) can develop dilated cardiomyopathy. In these cases, if the extrasystole are reduced or removed (for example, via ablation therapy) the cardiomyopathy usually regresses.
Dilated cardiomyopathy also occurs more frequently in pregnancy than in the normal population. It occurs late in gestation or several weeks to months postpartum as a peripartum cardiomyopathy. It is reversible in half of cases.
Read more about this topic: Dilated Cardiomyopathy