Ischaemia and infarction
Inferior STEMI
ST elevation in II, III and aVF with reciprocal change in aVL — and a right ventricle you must check before giving nitrates.
What you see
- ST elevation in the inferior leads II, III and aVF.
- Reciprocal ST depression in aVL, and often in I.
- Bradycardia and AV block are common — the RCA supplies the SA and AV nodes in most people.
- ST elevation in III greater than in II, with depression in I, favours RCA over circumflex.
Why it looks like that
The right coronary artery supplies the inferior wall, the AV node in about 90% of people, and the right ventricle through its proximal marginal branches. Occluding it therefore produces the infarct, the conduction block and the preload-dependent circulation all at once.
What to do
- Record right-sided leads (V4R) in every inferior STEMI before giving anything that drops preload.
- Primary PCI. Atropine and, if needed, temporary pacing for symptomatic high-grade block — which usually recovers.
- If the RV is involved, the patient is preload dependent: fluid load, and avoid nitrates and opiates.
The trap
Giving GTN to an inferior STEMI with right ventricular involvement can cause abrupt, profound hypotension. The question often makes this concrete: chest pain, inferior ST elevation, clear lungs, raised JVP, then a systolic pressure of 70 after a nitrate spray.
More in ischaemia and infarction
Anterior STEMI
Convex ST elevation across the anterior chest leads — the LAD occlusion you cannot afford to sit on.
Posterior myocardial infarction
Tall R waves and ST depression in V1–V3 — a STEMI viewed from behind, and easy to call NSTEMI by mistake.
Wellens' syndrome
Deep or biphasic T waves in V2–V3 in a pain-free patient — critical LAD stenosis waiting to declare itself.
De Winter T waves
Upsloping ST depression with tall symmetrical T waves in the chest leads — an LAD equivalent without the elevation.