[Electron microscopic study of the myocardium in 2 cases of primary systemic amyloidosis]

The authors describe two cases with primary systemic amyloidosis advancing with the picture of progressing cardiac insufficiency, clinically not distinguished. Electron microscopic study of myocardium was performed. The ultrastructural data indicate that the most likely source for synthesis of amyloid in myocardium, in primary systemic amyloidosis, are the active fibroblasts, established in interstitium.