ST Elevation Equivalents

Introduction to ST Elevation Equivalents

The American College of Cardiology states that ST elevation equivalents are ECG patterns that indicate acute coronary occlusion requiring emergent reperfusion therapy despite lacking classic ST elevation, including posterior MI, right ventricular MI, and de Winter T-waves 1

The European Heart Journal recommends that posterior MI should be managed as a STEMI 2
Horizontal ST-segment depression in V1-V3 with a dominant R-wave, upright T-waves in anterior leads, and prominent broad R-wave suggests posterior MI 1
The American College of Cardiology states that confirmation of posterior MI requires ST elevation ≥0.5 mm in at least one of the posterior leads V7-V9 1, 6, 2
The specificity of posterior MI diagnosis increases at a cut-point >0.1 mm ST elevation in posterior leads, and this higher threshold should be used in men <40 years old 6
The American College of Cardiology recommends recording posterior leads V7-V9 when there is high clinical suspicion for acute circumflex occlusion, especially with initial non-diagnostic ECG or isolated ST depression in V1-V3 6, 2

The American College of Cardiology states that right ventricular MI occurs with inferior wall infarction and requires specific management considerations 7, 3
The European Heart Journal recommends recording right-sided precordial leads (V3R and V4R) during acute inferior-wall MI to identify concomitant right ventricular involvement 7, 2, 8
ST elevation >0.5 mm in V3R or V4R provides supportive criteria for right ventricular infarction 6, 2
The American College of Cardiology states that standard V1 can be considered equivalent to V2R, and standard V2 equivalent to V1R within the right-sided electrode array 7, 3

The American College of Cardiology states that new or presumably new LBBB with ischemic symptoms should prompt urgent coronary angiography, but is NOT automatically a STEMI equivalent requiring immediate reperfusion 1, 8
The European Heart Journal recommends that concordant ST elevation in leads with positive QRS deflections is one of the best indicators of ongoing MI with an occluded infarct artery 8
LBBB should NOT be considered diagnostic of acute MI in isolation 9

The American College of Cardiology states that de Winter T-waves represent hyperacute proximal LAD occlusion and require immediate reperfusion 1
Tall, prominent, symmetrical T-waves arising from upsloping ST depression >1 mm at the J-point in precordial leads are characteristic of de Winter T-waves 1
The European Heart Journal states that these represent hyperacute changes that may precede classic ST elevation 2

The European Heart Journal states that ventricular pacing prevents interpretation of ST-segment changes and may require urgent angiography to confirm diagnosis 2, 8
Reprogramming the pacemaker to allow evaluation of intrinsic rhythm may be considered in non-pacemaker-dependent patients, without delaying invasive investigation 2, 8

The European Heart Journal states that ST elevation in aVR with multilead ST depression should be managed as NSTE-ACS, NOT as a STEMI equivalent 10
Fibrinolytic therapy should NOT be administered to patients with ST depression associated with ST elevation in aVR 10

The American College of Cardiology states that broad, asymmetric, peaked T-waves may be seen early in STEMI before ST elevation develops 1
Serial ECGs over very short intervals are useful to assess for progression to STEMI 1
The European Heart Journal states that some patients with acute coronary occlusion present very early with hyperacute T-waves preceding ST elevation 2, 8

The American College of Cardiology recommends immediately obtaining posterior leads (V7-V9) if ST depression in V1-V3 or suspected circumflex occlusion 6, 2
The European Heart Journal recommends obtaining right-sided leads (V3R-V4R) if inferior MI is present 2, 8
Serial ECGs at short intervals should be performed to detect dynamic changes or evolution to STEMI 1, 2
Urgent coronary angiography should be considered even without diagnostic ST elevation if suspicion of ongoing ischemia remains high 2, 8