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Rhythm

Anterior STEMI

Content last updated · 2 min read ·

This is the date the draft was written, not a medical review date.

Anterior ST-elevation myocardial infarction shows ST elevation in the anterior precordial leads, usually from occlusion of the left anterior descending artery. It involves a large territory of left ventricle and has a high risk of heart failure and arrhythmia.

ECG criteria

  • New J-point ST elevation in two contiguous leads, using Fourth Universal Definition thresholds: 1 mm or more in all leads except V2-V3.
  • In V2-V3: 2 mm or more in men aged 40 or over, 2.5 mm or more in men under 40, 1.5 mm or more in women.
  • Anterior territory leads V1 to V4 (extending to V5-V6 and I, aVL in extensive anterolateral infarction).
  • Reciprocal ST depression in the inferior leads (II, III, aVF) may be present.
  • Evolution over time: hyperacute T waves, then Q waves and T inversion; proximal LAD occlusion may add new right bundle branch block or fascicular block.

Mechanism

Acute thrombotic occlusion of the left anterior descending artery, usually on a ruptured or eroded atherosclerotic plaque, causes transmural ischaemia of the anterior wall and septum. The injury current shifts the ST segment toward the overlying leads and produces reciprocal depression in the opposite leads.

Common causes

  • Atherosclerotic plaque rupture or erosion with thrombosis in the left anterior descending artery (the usual cause).
  • Risk factors: smoking, diabetes, hypertension, dyslipidaemia, family history, older age.
  • Less common: coronary spasm, spontaneous coronary artery dissection, embolism, cocaine use.

Management principles

STEMI is a time-critical emergency: the principle is rapid reperfusion, preferably by primary percutaneous coronary intervention, or fibrinolysis when this cannot be delivered in time, within the local STEMI pathway and protocol. Antithrombotic and supportive therapy and complication management follow local guidelines, for example the ESC acute coronary syndrome guidelines.

High-level principles for study. Treatment decisions follow local guidelines and the clinical situation.

Pitfalls and mimics

  • Early repolarisation, pericarditis, left ventricular hypertrophy, LBBB and ventricular aneurysm can all mimic anterior ST elevation; compare with a previous ECG and the clinical picture.
  • De Winter pattern (upsloping ST depression with tall T waves in the precordial leads) is an STEMI equivalent without classic ST elevation.
  • A single early normal ECG does not exclude evolving infarction; repeat serial ECGs and use high-sensitivity troponin.

Practise in the ECG trainer — Recognise this pattern on generated tracings.

References

  1. 2023 ESC Guidelines for the management of acute coronary syndromes. European Society of Cardiology (2023) — Tier 2 (guidelines / primary literature)
  2. Fourth Universal Definition of Myocardial Infarction (2018). ESC / ACC / AHA / World Heart Federation (2018) — Tier 2 (guidelines / primary literature)
  3. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier, 12th edition (2022) — Tier 3 (textbook)

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