[Prevention of postischemic reoxygenation disturbances of heart function by using adaptation to altitude hypoxia]

The influence of adaptation to altitude hypoxia (2100 m) on rat myocardial contractility was examined during transitory ischemia induced by ligation of the descending branch of the left coronary artery and subsequent reperfusion. In control animals and those after adaptation, ischemia caused the same depression of heart function, while during reperfusion, the animals after adaptation, unlike the control ones, showed partial recovery of contractile function. Evaluation of heart function after ischemia and reperfusion demonstrated that the hearts of the animals after adaptation preserve the ability to bear the maximal isometric load on the level attained during adaptation to hypoxia, while the control animals experience substantial disorders of heart function because of ischemia and reperfusion. Thus, adaptation to altitude hypoxia increases the heart resistance to the damages that occur during reoxygenation.