This ECG is typical posterior MI  with deep horizontal STD in V1-V3. Patient was transferred to SCGH cathlab  priority 1, loaded with Aspirin 300 mg and Heparin 5000 U iv as per their cardiology advice.

Posterior STEMI:

• Isolated 3-11 %
• Usually in context of an inferior or lateral STEMI
• Horizontal STD
• Tall, broad RW > 30 ms
• Upright TW
• R/S >1 in V2

The progressive development of pathological R waves in posterior MI mirrors the development of Q waves in anteroseptal STEMI

Perform V7-V8-V9 ECG – shows STE – only 0.5 mm is enough to diagnose STEMI.

See the attached file for posterior leads placement.

Thanks to Dr Svetlana Trandos for preparing this case