1. Inferior/Posterior MI and 15 Lead ECG
Prepared by Shane Barclay MD

2. Regular 12 lead ECG was meant to look mainly at the left ventricle.

3. The 15 Lead ECG
Looks also at the posterior wall of the left ventricle and the right ventricle

4. Indications – 15 lead ECG
Any Inferior AMI (but especially accompanied by ST- depression in V1 to V3)
ST-depression in V1 – V3 on its own in symptomatic ACS patient

5. Many Variations – one option

6. 15 lead ECG as done in most hospitals
Run standard 12-lead
Lead V4R: 5th IC space midclavicular on right side
Same as left side V4
Attach V4 wire to the V4R position

7. 15 Lead ECG Posterior leads V8: 5th IC space midscapular line
V9 goes between V8 and the spine
Place Lead V5 wire on V8 and V6 wire on V9
Acquire the second 12-lead
Re-label the new leads

8. Quick Review of QRS

9. Normal QRS

10. T Wave Inversion – ‘ischemia’

11. ST Elevation/Depression – ‘Injury’

12. Q waves – infarction/necrosis

13. Looking differently at ST Elevation/Depression – ‘Injury’

14. ST Elevation/Depression – inverted/mirror image
Now the ‘injury’ can look like ST elevation – ischemia. This is known as reciprocal changes.

15. ST Elevation/Depression – inverted/mirror image

16. Inferior MI (lead II,III,AVF)
Always look for reciprocal changes in AVL – i.e. ST depression.
Can occur even before ST elevation in the inferior leads.

17. Note ST depression in AVL

18. Inferior MI note AVL when inverted looks almost identical to Lead III.

19. Posterior MI

20. Posterior MI Look for ST Changes in V1-3 leads

21. Is this just anteroseptal ischemia?

22. Look for Reciprocal changes

23. So beware of “Anteroseptal Ischemia’
Look for Posterior MI

24. So to reiterate Indications – 15 lead ECG
Any Inferior AMI (but especially accompanied by ST- depression in V1 to V3).
ST-depression in V1 – V3 on its own in symptomatic ACS patient.

25. 15 Lead Practice cases

26. 15 Lead ECG

27. Inferior/Posterior/RVI

28. Although you see Q wave/ST elevation in V8-9, consistent with posterior MI, if you ‘invert’ V1-3 you see a ‘posterior infarct’ pattern without even having the 15 lead ECG.

29. Inferior MI

30. Inferior-Posterior MI

31. Inferior/Posterior

32. The End !