CourseKardio Beta

STEMI: recognising and localising

ST-elevation criteria, localisation, common differentials.

9 min read

Learning objectives

  • You know the universal ST-elevation criteria for STEMI.
  • You can derive the anatomical localisation of a STEMI from the 12-lead ECG.
  • You know the key differential diagnoses of ST elevation.

The ST-elevation myocardial infarction (STEMI) is an acute diagnosis made primarily on the 12-lead ECG — fast, reproducible, with clear thresholds.

Example: anterior STEMI (V1–V4, convex ST elevation), generated with the sibling ECGGenerator project. Use the „Open in ECG generator“ link to change pathology, rate and axis.Open in ECG generator

ST-elevation criteria (4th universal definition)

ST elevation must be present in at least two contiguous leads, measured at the J-point. Thresholds:

  • V2–V3: ≥ 0.2 mV (men ≥ 40 yrs) · ≥ 0.25 mV (< 40 yrs) · ≥ 0.15 mV (women)
  • all other leads: ≥ 0.1 mV
  • V3R/V4R (right ventricular): ≥ 0.05 mV (men < 30 yrs: ≥ 0.1 mV)

Localisation on the ECG

LocalisationLeads with elevationLikely vessel
AnteroseptalV1–V4proximal LAD
AnterolateralV3–V6, I, aVLdistal LAD / LCx
Isolated lateralI, aVL, V5, V6LCx / diagonal
InferiorII, III, aVFRCA (often) / LCx
Posteriorreciprocal ST depression V1–V3, R/S > 1 in V2distal RCA / LCx
Right ventricularV4R (V3R)proximal RCA

Differential diagnoses of ST elevation

  • Pericarditis (concave, diffuse, PR depression)
  • Early repolarisation (J-point elevation with notch, often young/male)
  • Left bundle branch block (apply Sgarbossa criteria)
  • LV aneurysm (persistent ST elevation weeks after MI)
  • Brugada pattern (V1–V2, "coved type")
  • Hyperkalaemia, Hypothermia (Osborn wave)

Mini-quiz

1 / 3

Which leads are typically affected in an inferior STEMI?

Take-aways

  • STEMI criteria: ST elevation at the J-point in two contiguous leads; thresholds depend on age and sex.
  • Localisation: anteroseptal V1–V4, lateral I/aVL/V5/V6, inferior II/III/aVF, posterior — reciprocal depression in V1–V3.
  • Important differentials: pericarditis, early repolarisation, LBBB, LV aneurysm, Brugada pattern.

Mark the lesson once you have worked through it – synced across devices with an account.