Cardiomyopathies: is it time for a molecular classification?

Primary myocardial diseases have always attracted the interest of the scientific community because of their obscure aetiopathogenesis. For years there was a confusion and controversy over their definition and classification. The 1995 WHO classification led to major advancements such as the introduction of a unified terminology, the official recognition of novel entities (arrhythmogenic right ventricular and idiopathic restrictive cardiomyopathies) and the definitive clarification that inflammatory heart disease has to be regarded as a cardiomyopathy. However, according to the new definition of cardiomyopathies as diseases of the myocardium associated with cardiac dysfunction, they should include not only forms with depressed contractility and impaired diastolic function, but also conduction and rhythm disturbances and enhanced arrhythmogenicity. Moreover, the recent development of molecular genetics, with the discovery of a genetic background in several forms previously defined of unknown origin, raises the need of a debate on a possible classification based on genomics.