Cardio 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
r wave amplitude should ……….. from v1-6
increase
what is the general rule of t waves
should not be more than half the size of the qrs
what does prwp stand for?
poor r wave progression
how do you calculate corrected qt?
QT (in milliseconds)/ square root of R-R (IN SECONDS)
WHAT IS THE NORMAL QT?
400ms (0.4s)
in axis deviation, if both lead one and avl are down then the axis would be
indeterminate
which wave grows across chest leads v1-6? what is this called?
r wave = r wave progression
which leads are good at helping you determine rhythm and by looking at the p waves?
lead 2 or V1
when you are describing rhythm what would you say?
not regular or irregular – you would say sinus rhythm/ sinus tachycardia/ atrial flutter etc
how do you treat heart block
pacemaker
which one could get you in legal shit if you miss on an ecg
heart block
which types of heart block may be normla
1st degree and mobitz type 1
what are escape beats
come late because you didnt get a normal beat (back up rhythm)
what are ectopic beats
beats that arrive early
what is the definition of sinus rhythm
each p wave precedes a qrs and each qrs follows a p wave
at what rate do the atria usually beat in atrial flutter? what does this mean for the ventricular beat?
usually atria go at 300bpm
ventricles usually beat at a derivative of this (so 100 75 150 etc)
how can you slow the heart rate down in svt in order to see the rhythm properly?
vagal maneuvres
adenosine
what is a delta wave?
slurred upstroke on the r wave seen in WPW
How do you determine if there is BBB and if so which type?
step 1 - is the qrs broad? qrs >120ms (cannot be narrow needs to be broad)
step 2 - is it right bbb? (RSR pattern in V1 up down up / or M pattern)
step 3 - if answer to above qs is no - – left bbb
if you have a lbbb or rbbb with a tachycardia
broad complex tachycardia (vtach or a narrow complex tachy with aberancy)
what does monomorphic mean
all look the same in teh tachy
what does polymorphic mean?
v tachy all looking different ie torsades de pointes
if you have an irregualr broad complex tachy you need to check that its not
AF with aberancy
what does abberancy mean?
problem in heart conducting system - change in length of beat with no change in refractory period
t wave inversion in what lead is normal
lead 3
treat tachy
- vagal manoevre
- adenosine
- cardiovert
treat vtach
amiodarone
cardiovert
dont give adenosine in ……. - you should give …….
WPW/ AF
shock q
st depression
ischaemia
what is seen in cocaine
st depression
ectopic beats can cause
vtachy
a normal ecg does not exclude
coronary artery disease
inferior - artery
rca
anterior - artery
LAD
lateral - artery
circumflex
signs of a posteiror infarction
t wave inversion
v1-3
normal v4-6
treat MI
mona + t
IV unfractionated heparin 5000 units
cath lab (if far from hospital then thrombolysis)
what is hypertrophy
increase in mass not volume
most common cause of hypertrophy
hypertension
how to diagnose hypertrophy
-ve sv2 + +ve RV5 >7 boxes
ST depression and hypertension
may not be ischaemia may be LVH with strain
if qrs is broad think
bbb
st elevation with pr depression
pericarditis
treat pericarditis
nsaids but check troponin just in case
