Effects of oxygen therapy on wall‐motion score index in patients with ST elevation myocardial infarction—the randomized SOCCER trial

Background Although oxygen (O 2 ) is routinely used in patients with acute myocardial infarction ( AMI ), it may have negative effects. In this substudy of the SOCCER trial, we aimed to evaluate the effects of O 2 ‐treatment on myocardial function in patients with ST elevation myocardial infarction ( STEMI ). Methods Normoxic (≥94%) STEMI patients were randomized in the ambulance to either supplemental O 2 or room air until the end of the percutaneous coronary intervention ( PCI ). The patients underwent echocardiography on day 2–3 after the PCI and once again after 6 months. The study endpoints were wall‐motion score index ( WMSI ) and left ventricular ejection fraction ( LVEF ). Results Forty‐six patients in the O 2 group and 41 in the air group were included in the analysis. The index echocardiography showed no significant differences between the groups in WMSI (1.32±0.27 for O 2 group vs 1.28±0.28 for air group) or LVEF (47.0±8.5% vs 49.2±8.1%). Nor were there differences at 6 months in WMSI (1.16±0.25 vs 1.14±0.24) or LVEF (53.5±5.8% vs 53.5±6.9%). Conclusion The present findings indicate no harm or benefit of supplemental O 2 on myocardial function in STEMI patients. Our results support that it is safe to withhold supplemental O 2 in normoxic STEMI patients.