Ultrastructure of myocardial cells in sheep with congestive heart failure induced by Pachystigma pygmaeum

Losses amongst ruminants as a result of ingesting Pachystigma pygmaeum are an economically important problem in Southern Africa. The deaths are due to congestive heart failure, and while most of the symptoms are documented, information on the ultrastructural changes which accompany myocardial degeneration during the disease has been only briefly reported. In this article the authors describe the electron microscopy of myocardial tissue of affected animals, which revealed degeneration of myocardial fibres, fibrosis of interstitium, an increase in number and size of mitochondria, duplication of nuclei and other abnormalities. The ultrastructural abnormalities observed might explain some of the cardiodynamic findings described in the literature.