ECGs Flashcards
What are the 12 steps of interpreting an ECG?
- Patient details
- Date and time of ECG
- Paper speed, calibration
- Rate
- Rhythm
- Axis
- P wave
- PR
- QRS
- ST
- T wave
12 Other (QTc and U waves)
What should the paper speed be?
25mm/s
What should the voltage calibration be?
1cm/mV or 2 large squares
How do you calculate rate
Count 30 big squares and number of R waves in that time x10
OR
300 / no. big squares in R-R
Which leads do you look at in axis deviation?
I, II, III
Which lead is most positive in normal heart? What do the other two show?
II
Other two are also positive
In right axis deviation what ECG changes are there?
Lead I negative
II and III positive
In left axis deviation what ECG changes are there?
Lead I positive
II and III negative
Where is lead I ?
Left side
Which leads show the anterior heart?
v1-v4
Which leads show the inferior heart?
aVF, II, III
Which leads show the left lateral heart?
aVL, v5, v6, I
Which leads show the right atrium?
aVR, v1
How big should a P wave be?
> /= 2 small squares
Bifid P wave indicates?
L atrial hypertrophy
Peaked P wave indicates?
R atrial hypertrophy
How long should PR interval be?
3-5 small squares
Abnormal PR interval can indicate what?
Heart block
PR int. of >5ss =?
1st degree heart block
Progressively longer PR int until a beat is skipped
2nd degree HB, Mobitz type 1 (or Wenkebach)
Normal PR int but with some beats skipped
Mobitz type 1 (second degree HB)
Complete dissociation between P waves and QRS complex
3rd degree HB
What should the length of the QRS be?
<3 ss
Increased QRS =?
Bundle branch block
What does RBBB look like?
On v1 and v6 the deflections repel (MaRRoW)
What does LBBB look like?
WiLLiaM on v1 and v6
What would you see in WPW syndrome?
delta waves and a short PR interval
What do you look for in the ST segment?
Elevation >1ss (infarction) and depression >1ss (ischaemia or posterior infarction)
ST changes in leads II, III and aVF is which artery?
Right coronary
ST changes in leads v1-v4 is which artery?
Left anterior descending
ST changes in leads aVL, v5, v6 and I is which artery?
Left circumflex
The reverse tick is where in the cardiac cycle and indicates what?
ST, digoxin toxicity
Tented T wave=
hyperkalaemia
Flat T wave-
hypokalaemia
Inverted T wave=
Normal in III, aVR and v1, otherwise could be ischaemia
What QTc interval is ABnormal? What does this indicate?
> 450ms predisposition to polymorphic VT
What do U waves indicate?
Normal or hypokalaemia
