Electron microscopic lesions of the myocardium of rats fed a low-magnesium diet.

Electron and light microscopic examination of the myocardium of rats fed a low-magnesium diet showed swelling of mitochondria with disintegration and degeneration of the mitochondrial cristae, focal fragmentation of the myocardial fibers, their focal fuchsinophilia and necrosis. These abnormalities were associated with deposition of calcium salts in the degenerated muscle fibers, their mitochondria as well as in the ground substance of connective tissue.