1. FACEMs, Emergency Department
Working with ECGs
Dr Cynthia Lim
Dr Dean Pritchard
FACEMs, Emergency Department
The Northern Hospital

2. ECG 123s
Measurement of electrical flow across the heart using electrodes placed on the chest and limbs
Deviation of electrical flow from normal pathways indicates cardiac anomaly or cardiac disease

3. The Leads Limb Leads Vectors aVR – Right arm aVL – Left arm
aVF – Left leg
Vectors
Flow of +ve current
I – R arm  L arm
II – R arm  L leg
III – L arm  L leg

4. The Leads
Chest leads V1 V2 V3 V4 V5 V6

5. Axis
Look at leads I and avF
If in left quadrant then look at lead II

6. Successive approximation method

7. ECG Morphology What do each of the waves mean?
P, QRS, ST segment, T wave, U wave
Whats are the normal durations of each segment?
PR, QRS, QT

8. Pick the Problem…
NORMAL ECG

9. ECG of 2 year old – normal or abnormal?
Higher rate, Partial RBBB pattern, Dominant R V1, R axis deviation

10. Chest Pain

11. The Barn Door…
Acute anterior ST elevation myocardial infarction

12. The Barn door
Acute inferior ST elevation myocardial infarction

13. What about this?
Septolateral Non-ST Elevation Myocardial Infarction

14. And this?
Acute Pericarditis

15. ACS – STEMI
Any ST dep except V1 or aVR (allowed in acute pericarditis)
ST elevation III > II
Horizontal or convex up ST elevation
New Q waves

16. ACS – acute pericarditis
PR dep multiple leads
Only reliably seen viral
transient
Low voltage and tachycardia = large pericardial effusion
Friction rub
Use T-P as baseline (not P-P interval)
If in doubt serial ECGs

17. T-wave Changes T-wave inversions May persist for months or permanently
STEMI – After the appearance of ST changes
NSTEMI – After a period of hyperacute T-wave changes
May persist for months or permanently