Mean peak troponin
was similar in the oxygen and no oxygen groups (57.4 mcg/L vs. 48.0 mcg/L; ratio, 1.20; 95%
confidence interval [CI], 0.92 to 1.56; P=0.18). There was a significant increase in mean peak
CK in the oxygen group compared to the no oxygen group (1948 U/L vs. 1543 U/L; means ratio,
1.27; 95% CI, 1.04 to 1.52; P= 0.01). There was an increase in the rate of recurrent myocardial
infarction in the oxygen group compared to the no oxygen group (5.5%vs.0.9%, P=0.006) and an
increase in frequency of cardiac arrhythmia (40.4% vs. 31.4%; P=0.05). At 6-months the oxygen
group had an increase in myocardial infarct size on CMR (n=139; 20.3 grams vs. 13.1 grams;
P=0.04).