Ischemic ST‐Segment Depression Maximal in V1–V4 (Versus V5–V6) of Any Amplitude Is Specific for Occlusion Myocardial Infarction (Versus Nonocclusive Ischemia)

BACKGROUND: Occlusion myocardial infarctions (OMIs) of the posterolateral walls are commonly missed by ST‐segment–elevation myocardial infarction (STEMI) criteria, with >50% of patients with circumflex occlusion not receiving emergent reperfusion and experiencing increased mortality. ST‐segment depression maximal in leads V1–V4 (STDmaxV1–4) has been suggested as an indicator of posterior OMI. METHODS AND RESULTS: We retrospectively reviewed a high‐risk population with acute coronary syndrome. OMI was defined from prior studies as a culprit lesion with TIMI (Thrombolysis in Myocardial Infarction) 0 to 2 flow or TIMI 3 flow plus peak troponin T >1.0 ng/mL or troponin I >10 ng/mL. STEMI was defined by the Fourth Universal Definition of Myocardial Infarction. ECGs were interpreted blinded to outcomes. Among 808 patients, there were 265 OMIs, 108 (41%) meeting STEMI criteria. A total of 118 (15%) patients had “suspected ischemic” STDmaxV1–4, of whom 106 (90%) had an acute culprit lesion, 99 (84%) had OMI, and 95 (81%) underwent percutaneous coronary intervention. Suspected ischemic STDmaxV1–4 had 97% specificity and 37% sensitivity for OMI. Of the 99 OMIs detected by STDmaxV1–4, 34% had <1 mm ST‐segment depression, and only 47 (47%) had accompanying STEMI criteria, of which 17 (36%) were identified a median 1.00 hour earlier by STDmaxV1–4 than STEMI criteria. Despite similar infarct size, TIMI flow, and coronary interventions, patients with STEMI(−) OMI and STDmaxV1–4 were less likely than STEMI(+) patients to undergo catheterization within 90 minutes (46% versus 68%; P=0.028). CONCLUSIONS: Among patients with high‐risk acute coronary syndrome, the specificity of ischemic STDmaxV1–4 was 97% for OMI and 96% for OMI requiring emergent percutaneous coronary intervention. STEMI criteria missed half of OMIs detected by STDmaxV1–4. Ischemic STDmaxV1–V4 in acute coronary syndrome should be considered OMI until proven otherwise.