Correlation between index electrocardiographic patterns and pre‐intervention angiographic findings: Insights from the HORIZONS‐AMI trial

Objectives: To improve ECG interpretation accuracy in patients with chest pain prior to activation of the cardiac catheterization laboratory for primary percutaneous coronary intervention (PPCI). Background: Despite current guideline‐based ECG criteria, challenges remain in optimizing the rate of appropriate catheterization laboratory activation. Methods: The HORIZONS‐AMI trial enrolled 3,602 patients with chest pain consistent with myocardial infarction (MI). ECG and angiographic core laboratory databases were analyzed for correlation between the qualifying study ECG and the baseline coronary angiogram. Results: LAD occlusion manifested in >80% of cases as ST‐segment elevation in leads V2 and V3, while the culprit vessel was the RCA and LCx in 75 and 25% of cases, respectively, for inferior MI ECG patterns. The study threshold of ≥1.0 mm ST‐segment elevation in ≥2 contiguous ECG leads was not met in 189 (5.3%) patients. When stratified by culprit artery, the prevalence of reciprocal ST‐segment depression ranged from 24 to 88%, being least common for lesions in the mid‐ and distal left anterior descending artery. Despite study eligibility, no posterior MIs were enrolled. Only 36 LBBB cases were identified (25% of whom did not undergo PCI), and 5 of 11 left main coronary occlusions (45%) had ST‐segment elevation in lead aVR. Conclusions: The present study confirms prior ischemic ECG findings predicted by vectorcardiography, validates certain ECG patterns as reliable surrogate markers for acute coronary occlusion, and provides novel insights correlating index ECG ischemic changes and pre‐intervention coronary angiography. These results may enhance the rate of appropriate catheterization laboratory activation. © 2011 Wiley Periodicals, Inc.