Effects of allopurinol on tissue oxygen tension of the ischemic myocardium

The effects of allopurinol on the myocardial oxygen metabolism were studied in dogs with acute coronary artery occlusion. Upon occlusion of the contributory branch of the coronary artery, myocardial pO2, as measured with an improved polarographic technique, decreased to various lower values depending on the site of the electrode inserted. In the slightly ischemic myocardium, where myocardial pO2 decreased less than 50% of the control by the coronary occlusion, administration of allopurinol brought about a further diminution in myocardial pO2. In the severly ischemic myocardium, where myocardial pO2 decreased more than 50% of the control upon the coronary occlusion, no significant change was observed following allopurinol infusion. Theoretical beneficial effects of allopurinol on the ischemic myocardium by preserving functional purine bases might be offset by the aggravation of the negative oxygen balance in the ischemic but still viable myocardium following administration of allopurinol.