Effect of oxygen tension and cardiovascular operations on the myocardial antioxidant enzyme activities in patients with tetralogy of Fallot and aorta-coronary bypass

Since the chronically cyanotic myocardium appears to be more susceptible to reperfusion injury after cardiac operations than the noncyanotic myocardium, we studied the associationbetvveen the preoperative arterial oxygen tension and the myocardial superoxide dismutase, catalase, and glutathione peroxidase activities. Fourteen patients with tetralogy of Fallot scheduled for elective operations had baseline arterial blood gas measurements done before operation. During the operation right ventricular biopsy specimens were then for enzyme analysis immediately before cold blood cardioplegic arrest and 20 minutes after crossclamp removal