Associations with resolution of ST-segment elevation myocardial infarction criteria on out-of-hospital 12-lead electrocardiograms following resuscitation from cardiac arrest

Introduction: A previous study found that following out-of-hospital cardiac arrest (OHCA), 67% of out-of-hospital 12-lead electrocardiograms (ECGs) diagnostic for ST-segment elevation myocardial infarction (STEMI) changed to non-STEMI on repeat emergency department (ED) ECG. Here we evaluated associations with resolution of STEMI on ED ECG. Methods: In this secondary analysis of a previous retrospective study, adults (≥18 years) with return of spontaneous circulation (ROSC) following OHCA, at least 1 out-of-hospital and ED ECG and transport to the study hospital were entered. We analyzed variables suspected of influencing ischemic changes on ECG including arrest characteristics, treatment interventions, resuscitation duration, and out-of-hospital and ED ECG acquisition times. Results: Forty-nine of 176 patients entered had out-of-hospital ECGs diagnostic for STEMI, and 33/49 (67%) had resolved STEMI upon ED evaluation. Shorter resuscitation time (13 [interquartile range 5–18] vs 21 [14–28] minutes), p = 0.007), less epinephrine (3 [1–4] vs 5 [2–10] milligrams, p = 0.018), lower incidence of norepinephrine (5/33 (15%) vs 11/16 (69%), p ≤ 0.001), less time from ROSC to out-of-hospital ECG acquisition (5.5 [1–8] vs 8.5 [7–14] minutes, p = 0.044), and more time between out-of-hospital and ED ECG acquisition (34 [25–52] vs 21 [14–27] minutes, p = 0.001) were associated with resolution of out-of-hospital STEMI on ED evaluation. More defibrillations were associated with increased ischemia on ED ECG for patients with non-STEMI out-of-hospital ECGs. Conclusion: ROSC patients with STEMI on out-of-hospital ECG commonly resolve in the ED (67%). These identified associations may better inform clinical decision making. Post-ROSC out-of-hospital 12-lead ECGs should be repeated on arrival in the ED.