Respiratory and oxidative phosphorylation of myocardial mitochondria in hypertrophied and failing hearts.

Respiratory and oxidative phosphorylation activity of mitochondria was studied in the course of the adaptation of the heart to haemodynamic overload in rabbit due to aortic valve insufficiency. In the period of developing cardiac hypertrophy, the rate of oxygen consumption in stage 3, i.e. in the stage of ATP formation, and the phosphorylation rate significantly increase. In the period of regression of cardiac hypertrophy, which precedes heart failure, the respiratory and oxidative phosphorylation activity does not significantly change. In a failing heart, the respiratory rate in stage 3 returns to normal and the phosphorylation rate increases in comparison with normal rabbits. The results of the study show that in the myocardium of hypertrophied non-failing as well as failing heart after prolonged haemodynamic overload, the primary function of mitochondria, i.e. energy production is sufficiently preserved.