Recovery of the neonatal heart after normothermic ischemia : effect of oxygen and catalase

The objective of this study was to determine the effect of oxygen and the oxygen radical-scavenging enzyme catalase on the neonatal rabbit heart exposed to global ischemia. The experiments were performed with an isolated neonatal (7 to 10 days of age) working heart model in which normothermic (37 o C) ischemia was produced for 60 minutes. Left ventricular developed pressure, ratio of change of ventricular pressure to change in time, and aortic flow were measured before ischemia and 30 minutes after reperfusing the hearts with physiologic saline solution. In the control group (ischemia only), developed pressure and ratio of change of ventricular pressure to change in time recovered to 27% ± 3% (mean ± standard error of the mean) and 24% ± 7% of baseline; the hearts were incapable of ejecting (aortic flow=0)