[Morphologic changes in the myocardium following acute blood loss and subsequent resuscitation]

An electron microscopic investigation on reparative regeneration of the myocardium has been performed in dogs survived after clinical death resulted from loss of blood. Some regenerative processes already begin on the first hours after reanimation and they proceed on the background of certain distrophic and destructive changes. On the 3d-7th days of the restorative period, the intracellular regeneration of cardiomyocytes increases considerably; it is demonstrated by newly formed myofilaments in the foci of myofibrillar lysis, increasing content of small mitochondria, hyperplasia of the granular endoplasmic reticulum. Simultaneously, a great number of secondary lysosomes is forming; as a result, the cells are releasing themselves from the substances formed after decomposition and decay of some organelles. Myelin-like bodies are observed to be pushed out of the cardiomyocytes into the intercellular space. In fact, by the end of the second week after total ischemia the structure of the cardiac muscle is fully normalized. T-system of cardiomyocytes is the one which is the slowest to restore.