Controlled reperfusion augments metabolic and functional recovery of isolated rat heart after total ischemia

Metabolic and functional effects of a hypocalcium reperfusion solution (RS) with low oxygen content containing cl-glucose, trisamine, d-mannitol and I-aspartic acid have been studied in isolated rat hearts. The hearts were initially perfused for 20 min with the Krebs solution under constant left atrial filling pressure of 15 mm Hg and aortic perfusion pressure of 60 mm Hg. Then they were subjected to 30-min total normothermic ischemia followed by 30-min of reperfusion. The Krebs solution (control, n=16) or RS (n=11) were infused in retrograde mode with a rate of 4 ml/min during first 5 min of reperfusion. After that the hearts of both groups were reperfused in antegrade mode with the Krebs solution for 25 min under initial conditions. Short-term infusion of RS markedly improved postischemic functional recovery of cardiac function. After 30-min reperfusion coronary flow, an index of contractile function intensity, expressed as the left ventricle developed pressure-heart rate product, and cardiac work, calculated as the minute volume-aortic perfusion pressure product, recovered up to 92 +/- 1%, 77 +/- 11% and 61 +/- 1% of baseline values, respectively. In the control group the same indices were significantly lower and were 74 +/- 3%, 48 +/- 5% and 33 +/- 2%, respectively (p < 0.001). At the end of reperfusion hearts treated with RS compared with the control hearts showed higher myocardial levels of ATP, phosphocreatine (PCr) and total creatine (SCr). These metabolic findings indicate better recovery of energy state and lesser sarcolemmal damage of postischemic cardiomyocytes after RS infusion. Thus, optimization of administration mode and composition of reperfusion solutions is a promising tool to attenuate functional and metabolic disturbances of the postischemic heart.