ECG Flashcards
what does the p wave represent
atrial depolarisation
how long is the p wave (seconds and squares)
0.08-0.1s 2 small squares
how long is the qrs wave (seconds and squares)
<0.12s <3 small squares
how long is the pr interval (seconds and squares)
0.12-0.2s 3-5 small squares
what does the qrs wave represent
ventricular depolarisation
what does the t wave represent
ventricular repolarisation
what does the pr interval represent
av nodal delay
st
systole
tp
diastole
1 small box =
0.04s
1 large box =
0.2s
if heart rate regular
300/ no large squares between r-r
if heart rate irregular
Count the number of QRS complexes in 30 large squares, and then multiply by ten.
normal axis deviation shown on ecg
lead 1 and avf are upright
right axis deviation axis deviation shown on ecg
lead 1 down avf up
left axis deviation shown on ecg
axis deviation shown on ecg
what criteria diagnoses st elevation
• Greater than or equal to 1mm ST Elevation in 2 adjacent limb leads • Greater than or equal to 2mm ST Elevation in at least 2 contiguous precordial leads • New onset bundle branch block
how do you analyse an ecg in an osce
what are the 3 leads of an ecg
lead 1 = right arm left arm
lead 2 - right arm left leg
lead 3 - left arm left leg
inferior mi effects which arteries
left or right ca
anterior mi effects which arteries
LAD
what ecg changes could happen on the first day of a stemi
ST Elevation – first few hours
T wave inversion – first day
Q waves – first day
how would you calculate a regular heart rate on a patient with tachycardia?
1500/ small squares between two r waves
what are the 3 most common tracing problems
ac interference
muscle tremor
baseline wandering
what are the 6 key rhythm questions
if a signal travels toward a lead it will be
+ve
if a signal travels away from a lead it will be
-ve
5 large boxes =
1s
how to calculate the corrected qt interval?
qt/square root of rr
the p wave is normally inverted in lead
avr