Why STEMI equivalents matter: same urgency, different appearance
Traditional STEMI criteria require ST elevation ≥1mm in two contiguous limb leads or ≥2mm in precordial leads. But acute coronary occlusion — which requires emergent reperfusion — can present without meeting these criteria. STEMI equivalents are patterns indicating total or near-total coronary occlusion without classic ST elevation.
De Winter T-waves: J-point depression (1–3mm) with tall, symmetric, upright T waves in V1–V6. Caused by proximal LAD occlusion. No ST elevation is present — commonly misdiagnosed as early repolarization or hyperkalemia. These patients need cath lab activation now, not troponin-guided workup.
Wellens syndrome (reperfusion T-wave pattern): biphasic T waves (Type A) or deep symmetric T-wave inversions (Type B) in V2–V3 in a pain-free patient. Represents reperfused proximal LAD stenosis — the plaque has momentarily reperfused but remains critically narrow. These patients are at extremely high risk for sudden re-occlusion. Stress testing is contraindicated — they need urgent cardiology consultation and likely PCI.