Do STEMI Equivalents Post-ROSC Need Immediate Cath?

May 3, 2023

Written by Jason Lesnick

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In patients with ROSC after OHCA, these ‘STEMI equivalents’ do not appear to accurately diagnose ACS based on this study. 

Why does this matter?
Currently, if a post-ROSC ECG is obtained and there is not a STEMI, there is evidence that delayed cardiac catheterization is equivalent to immediate intervention (as we have covered here and here). However, if emergent cardiac catheterization showed benefit in patients who had post-ROSC ECGs with STEMI equivalents, this could change practice. 

STEMI equivalents are more equivocal than diagnostic after ROSC
This retrospective database review of patients ≥ 18 years of age from multiple centers in Japan with non-traumatic OHCA and VF or pulseless VT on arrival of EMS or to the ED who had ROSC obtained included 143 patients. 

The authors analyzed the following ‘STEMI equivalents’: isolated T-wave inversion, ST-segment depression, Wellens’ signs, and ST-segment elevation in lead aVR (which really should not be considered a STEMI equivalent). There were too few cases of De Winter ST-T waves, hyperacute T-waves, and resting U-wave inversions to analyze. 

The authors found that isolated T-wave inversion, low QRS voltage, and Wellens’ sign had high specificity, 0.95 (95%CI 0.87–0.99), 0.98 (0.92–1.00), and 0.92 (0.82–0.97), respectively, but positive likelihood ratios (LR +) were low (from 0.89 to 1.89 – not so great). 

The most important limitation of this study is that the diagnosis of ACS as a primary outcome was based on the clinical judgment of the physician expert rather than a universal definition of acute myocardial infarction. Another limitation here was that the timing of the ECG was unclear in this study, which is a key limitation, because the duration from ROSC to ECG would affect the ECG accuracy.

This is an interesting study, and kudos to the authors for trying to shed some light on this relatively common situation. The key takeaway is that we should continue to discuss these patients with our cardiology colleagues if we are concerned for ACS but recognize that without STEMI on post-ROSC ECG, an emergent catheterization is unlikely to happen based on current evidence, consistent with AHA and ESC guidelines.

Source
Diagnostic test accuracy of life-threatening electrocardiographic findings (ST-elevation myocardial infarction equivalents) for acute coronary syndrome after out-of-hospital cardiac arrest without ST-segment elevation. Resuscitation vol. 184 (2023): 109700. doi:10.1016/j.resuscitation.2023.109700