[Quantitative analysis of the mitochondrial ultrastructure of cardiomyocytes in rats adapting to altitude hypoxia].

A study was made of the quantitative characteristics of mitochondria of the myofibrillar, perinuclear and subsarcolemmal zones of cardiomyocytes during long-term adaptation of rats to an "altitude" of 9000 m in a pressure chamber. The data are presented on the role played by hypertrophic and hyperplastic processes occurring in the mitochondrial apparatus in supporting viability of cardiac cells at high altitude.