Working with ECGs
Dr Cynthia LimDr Dean Pritchard
FACEMs, Emergency Department The Northern Hospital
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
The Leads
• Limb Leads– 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
The Leads
• Chest leads
– V1– V2– V3– V4– V5– V6
Look at leads I and avF
If in left quadrant then look at lead II
Axis
Successive approximation method
ECG Morphology
Pick the Problem…
NORMAL ECG
ECG of 2 year old – normal or abnormal?
Higher rate, Partial RBBB pattern, Dominant R V1, R axis deviation
Chest Pain
The Barn Door…
Acute anterior ST elevation myocardial infarction
The Barn door
Acute inferior ST elevation myocardial infarction
What about this?
Septolateral Non-ST Elevation Myocardial Infarction
And this?
Acute Pericarditis
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
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
T-wave Changes
• T-wave inversions– STEMI – After the
appearance of ST changes
– NSTEMI – After a period of hyperacute T-wave changes
• May persist for months or permanently
