Linear densities in mitochondria of human myocardial cells.

Ultrastructural study of myocardial biopsies from 5 patients who underwent myocardial revascularization procedures because of impending infarction showed mitochondria with linear densities. These densities, which occupied the intracristal space, appeared to have a high protein but low mineral content. It is suggested that linear densities may be an expression of severe, acute myocardial cell injury.