A classification serves to bridge the gap between ignorance and knowledge.1 Previously the cardiomyopathies were defined as “heart muscle diseases of unknown cause” and were differentiated from specific heart muscle disease (of known cause).2 With increasing understanding of etiology and pathogenesis, the difference between cardiomyopathy and specific heart muscle disease has become indistinct. The original classification described three types, which have become established clinical entities, and this terminology has been preserved. The cardiomyopathies are now classified by the dominant pathophysiology or, if possible, by etiological/pathogenetic factors.
Definition and Classification
Cardiomyopathies are defined as diseases of the myocardium associated with cardiac dysfunction. They are classified as dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy.
Dilated cardiomyopathy is characterized by dilatation and impaired contraction of the left ventricle or both ventricles. It may be idiopathic, familial/genetic, viral3 4 5 and/or immune,6 7 alcoholic/toxic, or associated with recognized cardiovascular disease in which the degree of myocardial dysfunction is …