Idiopathic cardiomyopathies. A review of pathologic studies and mechanisms of pathogenesis.

The purpose of this article is to provide a critical review of our current knowledge of the pathogenic mechanisms of human cardiomyopathy in the context of accepted morphologic findings (gross, microscopic, ultrastructural) and the clinical presentation of this disease. It is our intent to emphasize the numerous difficulties encountered in categorizing patients with cardiomyopathy to pursue investigations in the pathogenesis and origins of this puzzling cardiac condition. It is our belief that such difficulties stem primarily from the existing classification of cardiomyopathies, which is mostly empirical and somewhat vague. This is particularly true in regard to the dilated cardiomyopathies that probably encompass multiple entities grouped under the umbrella of cardiomegaly and dilation. The article's objective is to summarize clinical symptoms and signs, modalities of diagnostic investigations, and prognosis for each category of cardiomyopathy. However, the main purpose of this article is to present recent findings on the origins, possible autoimmune basis of the disease, and results of immunologic studies in patients with cardiomyopathy.