Abstract 9302: Electrocardiographic Criteria for ST-Elevation Myocardial Infarction in Patients with Left Ventricular Hypertrophy
Background: Patients with electrocardiographic (ECG) left ventricular hypertrophy (LVH) have ST segment repolarization abnormalities that are difficult to differentiate from an ischemic current of injury. ACC/AHA criteria diagnose ST-elevation myocardial infarction (STEMI) as ≥ 1 mm STE in two contiguous leads, and 2 mm if the STE are isolated to leads V1-V3.Additional criteria are much needed to correctly diagnose STEMI in patients with LVH.
Methods: We analyzed the ACTIVATE-SF database, a registry of consecutive Emergency Department STEMI diagnoses from 2 medical centers at UC San Francisco. Logistic regression was performed to identify ECG variables that predicted presence of an angiographic culprit lesion.
Results: We identified 79 patients with electrocardiographic LVH who underwent cardiac catheterization for consideration of primary angioplasty. Just 22 (28%) patients were found to have an angiographic culprit lesion. Patients with a culprit lesion had greater magnitude of ST elevation (3.0 ± 1.8 vs. 1.9 ± 1.0 mm, p = 0.005), more leads with ST elevation (3.1 ± 1.6 vs. 2.0 ± 1.8 leads, p = 0.002), and a greater ratio of ST segment elevation to R wave height (median 25% vs. 9.2%, p = 0.003). Among these univariate factors, adding the median ratio of ST segment to R wave height >25% to the ACC/AHA criteria significantly improved overall diagnostic discrimination: c-statistic 0.65 vs. 0.74, specificity 58 vs. 93%, sensitivity 64 vs. 73%, positive predictive value 40 vs. 78%, and negative predictive value 85 vs. 87%.
Conclusion: Most patients with chest pain, electrocardiographic LVH and diagnostic ST segment elevation by ACC/AHA criteria have no culprit lesion at angiography. A ratio of the ST segment to R wave magnitude > 25% increases specificity for diagnosis of STEMI without reducing sensitivity. This additional ECG criterion should appreciably improve STEMI diagnosis in LVH and lead to a more appropriate utilization of cardiac catheterization procedures.
- © 2011 by American Heart Association, Inc.