View source for 39. ECG in acute myocardial infarction

Acute myocardial infarction (AMI) is characterised by ischaemia and infarction of the myocardium. These pathological processes cause characteristic signs of the ECG that we can use to diagnose it (in addition to cardiac enzymes and symptoms). Most of these signs appear only in the leads that correspond to the where the myocardial infarction occurs.

According to the location of the infarct, the following leads often show signs:
{| class="wikitable"
!Localization of infarct
!Affected leads
|-
!Septal
|V1 + V2
|-
!Anteroseptal
|V1 + V2 + V3 + V4
|-
!Anterior
|V2 + V3 + V4
|-
!Extensive anterior
|I + aVL + V1 + V2 + V3 + V4 + V5 + V6
|-
!Anterolateral
|I + aVL + V6
|-
!Apical
|V5 + V6
|-
!Inferior
|II + III + aVF
|-
!Posterior
|Mirror signs in V1 + V2 + V3
|-
!Right ventricle
|V1 + V2 + (V4R + V5R)
|}
The progression of AMI follows three phases, the hyperacute, acute and chronic phases.