The relaxation of sarcomeres in ischemic injury of myocardium.

Polarization-microscopic and micrometric investigations of the myocardium during infarction at autopsy and in experimental ischemic conditions, has shown that one of the earliest and most typical morphological signs of ischemic myocardium is sarcomere relaxation. The latter is expressed by the loss of contractility of muscle cells in life time and in strongly frozen corpses, and due to the effects of fixatives. Increase of the percentage of relaxed sarcomeres parallels the duration of experimental ischemia and the time after myocardial infarction. This allows the indirect calculation of irreversible cell change.