Local hospital vs. core-laboratory interpretation of the admission electrocardiogram in acute coronary syndromes: increased mortality in patients with unrecognized ST-elevation myocardial infarction

AIMS: Previous analyses suggest only modest agreement between local site and core-laboratory (core-lab) electrocardiogram (ECG) interpretation in patients with acute coronary syndromes (ACSs); however, this has not been well examined outside of clinical trial populations. METHODS AND RESULTS: Patients (n = 5277 from 51 hospitals; 4916 with 1 year vital status) participating in the Canadian ACS Registry who were hospitalized with an ACS and had an interpretable initial ECG were included in this study. Core-lab ECG interpretation was blinded to site interpretation and outcomes. There was moderate agreement between site and core-lab regarding the predominant ECG findings (kappa = 0.49). Patients with core-lab-defined ST-elevation and cardiac marker elevation (n = 1202) not classified as ST-elevation by the site were less likely to receive acetylsalicylic acid (ASA) (90 vs. 96%, P < 0.0001), heparin (91 vs. 95%, P = 0.04), and reperfusion therapy (14 vs. 76%, P < 0.0001) than patients for whom there was agreement that ST-elevation was present. After adjusting for other validated prognostic factors, site-unrecognized ST-elevation was independently associated with higher mortality (odds ratio = 2.21; 95% CI, 1.46-3.36; P < 0.001). CONCLUSIONS: In patients with ACS, there was only moderate agreement between core-lab and site interpretation of the initial ECG. Site-unrecognized ST-elevation myocardial infarction was associated with underutilization of evidence-based therapies and increased 1-year mortality.