Dilated Cardiomyopathy Hypertrophic Cardiomyopathy Arrhythmogenic right ventricular dysplasia Restrictive Cardiomyopathy Idiopathic Secondary Amyloidosis2 Loeffler's eosinophilic endocardial fibrosis2 Tropical endocardial fibrosis (Davies disease) Unclassified cardiomyopathies Mitochondrial cardiomyopathy Fibroelastosis Noncompacted myocardium Systolic dysfunction with minimal dilatation3

Definition and Classification The cardiomyopathies are a diverse group of myocardial diseases that are characterized by chronic ventricular dysfunction. The clinical classification of cardiomyopathy is based on hemodynamic and echocardiographic abnormalities, and consists of dilated cardiomyopathy, hypertrophic cardiomyopathy, and restrictive cardiomyopathy. Recently, arrhythmogenic right ventricular dysplasia has been added to this classification [1] (Table 1). Hypertrophic and right ventricular cardiomyopathies have fairly distinctive morphological manifestations. Dilated and restrictive cardiomyopathies, on the other hand, are a more heterogeneous group of disorders without uniform histologic features. For this reason, the modifier "idiopathic" often precedes restrictive and dilated cardiomyopathy to emphasize that a variety of specific cardiac and systemic illnesses that may mimic these conditions has been ruled out. Secondary cardiomyopathies are termed "specific cardiomyopathies" in the recent World Health Organization classification [1] , and are primary diseases or the valves or coronary arteries, or are systemic illnesses with cardiac manifestations.