REDUCED AEROBIC METABOLIC EFFICIENCY IN POSTISCHEMIC MYOCARDIUM DYSFUNCTION IN RATS - ROLE OF AGING

It has been suggested that aging may enhance the deleterious effects o f myocardial ischemia-reperfusion. This study evaluates the relationsh ip between oxygen consumption and functional impairment during reperfu sion following myocardial ischemia in adult and senescent rat hearts. Global ischemia induced a marked impairment of contractile function wh ich was significantly higher in senescent than in adult hearts. During reperfusion postischemic dysfunction was more evident in senescent he arts: at the 10th minute, the developed pressure recovered less (p < 0 .05) and end-diastolic pressure increased more (p < 0.05) in senescent than in adult hearts. However, oxygen consumption per unit of work wa s significantly higher throughout 60 min of reperfusion when compared to controls with no significant difference between adult and senescent hearts. This study demonstrates that following ischemia and reperfusi on depression of function and inappropriately high oxygen consumption were observed in both adult and senescent hearts. However, aging was a ssociated with greater contractile impairment, which occurred in the a bsence of further deterioration of metabolic efficiency of contraction .