Classification and differential diagnosis of the myocardiopathies

Abstract

HE MYOCAt/DIUM may be affected by a number of inflammatory, degenerative, or neoplastic processses whose principal manifestations are in other parts of the body. This discussion will be limited to disorders in which myocardial is of such clinical significance as to produce cardiac enlargement or congestive heart failure. Disorders which affect the myocardium have been classified in several ways. One group of writers 1 employs the term myocardial disease as inclusive of not only the idiopathic disorders of the myocardium but also of more generalized diseases when the myocardium is the principal site of involvement. For greater clarity, the present writer prefers a different classification. In this classification the term myocardial disease refers only to tho idiopathic disorder. This group probably will be found eventually to include several etiologic categories. Such terms as myocardosis, 2 idiopathic cardiac hypertrophy, 3 and idiopathic cardiomyopathy, 4 or cardiopathy 5 are probably synonymous with primary myocardial disease. The primary forms of myocardopathy probably represent a heterogeneous group of disorders and in many instances may begin as myocarditis. We have observed 3 patients in whom there was associated pericarditis, In 2 of these the illness began with the features of idiopathic pericarditis to be followed by a clinical course consistent with idiopathic myocarditis and in turn by tile myoeardopathy syndrome with prolonged congestive heart failure, persistent cardiac dilation, and other features described below. Other centers have reported a frequent association of pericarditis and the myocardopathy syndrome2 In some patients primary myocardopathy may result from nutritional, hereditary, or metabolic disorders. Secondary myocardial diseases are those in which the myocardial involvement is part of a generalized or specific process. The following is a proposed class~ification of myocardial diseases in accordance with the foregoing statemehts.