ECG Flashcards
P wave
atrial depolarisation
QRS complex
ventricular depolarisation
should be <0.12s (3 little square)
T wave
ventricular repolarisation
PR interval
time between atrial and ventricular depolarisation
should be 0.12-0.2s (3-5 small square)
QT interval
time for ventricular depol and repol
max 0.42s
ST segment
time between ventric depol and repol
what does small square =
0.04s
what does big square =
0.2s
what do 5 big squares =
1s
what do 300 big square =
1min
inferior leads
II, III, aVF
lateral leads
I, aVL, aVR, V5, V6
anterior leads
V3, V4
septal leads
V1, V2
normal cardiac axis
between -30 and + 90 degrees
calculating heart rate when rhythm is regular
no. big squares in one R-R interval divided by 300
calculating heart rate when rhythm is irrregular
no. QRS on rhythm strip x 6
normal cardiac axis signs ECG
II has more positive deflection than I and III
right axis deviation on ECG
III has most positive deflection
I is negative deflection
left axis deviation on ECG
I has most positive deflection
II and III negative deflection
1st degree heart block
fixed prolonged PR interval (>0.2s)
2nd degree heart block T1
progressive PR prolongation and then dropped QRS
2nd degree heart block T2
consistent PR prolongation with intermittent dropped QRS
3rd degree heart block
no association between P and QRS
Assessing QRS complex
width
height
morphology
delta wave
assoc w wolf parkinson white syndrome
ST segment
end S wave to start T wave
ST elevation
ST depression
tall T wave
> 5mm limb leads and >10mm chest leads
hyperkalaemia
inverted T wave
ischemia
bundle branch block
PE
left ventric hypertrophy
biphasic T wave
2 peaks
ichaemia, hypokalaemia
flattened T wave
ischaemia
electrolyte imbalance
