Dilated (congestive) cardiomyopathy: a syndrome of severe cardiac dysfunction with remarkably few morphological features of myocardial damage.

A review of 76 endomyocardial biopsies and 54 autopsies of patients with dilated cardiomyopathy (DCM) revealed features of hypertrophy and degenerative changes associated with long-standing hypertrophy. Long-term survivors had significantly heavier heart weights. Short-term survivors had heavier than normal right ventricular weights. No pathological findings supportive of a previous viral myocarditis, persistent slow virus infection or autoimmune process were observed. Hearts of autopsied DCM patients showed no significant difference from controls with regard to interstitial mononuclear cells. Morphometry failed to detect any difference in the fibrous tissue component between the DCM and control patients. Microscopic findings suggest that the cardiac failure of DCM is due to a potentially reversible functional abnormality. The cause of this is unknown, but the morphology suggests that future research should be directed by the premise that DCM represents a toxic-metabolic defect-deficiency state.