Ischemic ST-Segment Changes on Electrocardiogram in Acute Myocardial Infarction—Still Common?
Al-Darzi W, Nowak R, Hudson M, Moyer ML, Jacobsen G, and McCord J. Ischemic ST-segment changes on electrocardiogram in acute myocardial infarction-still common? J Gen Intern Med 2017; 32(2):S235-S236.
J Gen Intern Med
BACKGROUND: Prior studies report ischemic ST-segment changes on electrocardiogram (ECG) in 40-60% of patients with acute myocardial infarction (AMI) with important diagnostic and prognostic implications. Additionally, 1 to 6% of AMI patients had normal ECG on prior studies. These findings may have changed on the era of more sensitive cardiac troponin (cTn) assays.
METHODS: In a single-center we prospectively studied 569 patients who were evaluated for possible AMI in the emergency department from May 2013 to April 2015. Diagnosis of AMI was adjudicated by 2 independent physicians in accordance with the universal definition of AMI using all clinical information and required cTnI > 0.04 ng/ml (Siemens Ultra-cTnI). In situations where there was disagreement between the adjudicators, a third Cardiology adjudicator reviewed the case for final determination. Patients with ECG findings that led to immediate reperfusion therapy were excluded.
RESULTS: There were 45 (8%) patients with a diagnosis of AMI. Among AMI patients, the most common ECG findings were T-wave inversion 13 (29%) and normal 13 (29%) while 6 (13%) ECGs demonstrated ST Depression ≥ 1 mm. Comparing patients with and without ST-segment elevation or depression, there was non-significantly higher cTnI levels (13.2 ± 28.3 vs. 5.9 ± 15.6 ng/ml; p = 0.355).
CONCLUSIONS: ST-segment changes on ECG are becoming less common in AMI. This may relate to smaller AMIs identified by more sensitive cTn assays which should be verified in larger trials. (Table Presented).