Histochemical, ultrastructural and structural changes in primary cardiomyopathy and in cobalt cardiomyopathy.

Congestive cardiomyopathy (systolic pump failure) Glycogen is patchily increased in the myocardial fibres surrounding the nucleus and may also be found between myocardial fibrils. As a marker of mitochondrial activity, succinic dehydrogenase and NADH diaphorase are used which show a similar distribution to that of glycogen, i.e. increased activity can be seen in the perinuclear region and between fibrils. Acid phosphatase and non-specific esterases used as markers for lysosomal activity show also increased activity. The distribution is patchy throughout biopsy material. The histochemical changes reflect hypertrophy of the myocardium but we have been unable to find a specific enzyme alteration pathognomonic for congestive cardiomyopathy. Ultrastructural changes consist of an increase in mitochondria. In some instances mild mitochondrial swelling is evident with some degenerative changes in cristae and occasionally mitochondrial 'ghosts' are seen. An increase in lipofuscin granules and lipofuscin precursor granules has also been found. The contractile elements are preserved and long runs of fibrils are seen.