If there ST depression in the anterior leads (V2, V3 and V4), conduct a V7, V8 and V9 ECG on the posterior of the patient.

Do this by placing the V4, V5 and V6 leads on the left side of the patient’s back underneath the scapula, as shown in the figure below.

If 0.5mm or more of ST elevation is present in two or more of these leads then treat for posterior STEMI.

It is important to mark on the ECG paper that this is a posterior view of the patient’s heart.