ECG's Flashcards
What is an ECG?
A recording of the electrical activity of the heart.
Where does the electrical activity travel in the heart?
SA node (RA) to Bachmans bundle (LA) and AV node. Then to bundle of His and down bundle branches to Purkinje fibres through ventricles.
What is happening in depolarisation?
When sodium floods in a potassium floods out and the electrical wave moves.
Repolarisation is what?
When the sodium and potasium resore to normal.
Contraction is depolarisation or repolarisation?
depolarisation.
Relaxing of the cardiac muscles is depolarisation or repolarisation?
repolarisation.
Where are the lead placements of a 3 lead ECG?
red-right arm, yellow- left arm, black- right leg, green- left leg.
How many leads does a 3 lead ECG have?
4
Which way are the ‘pictures’ taken?
Right arm to left arm (lead 1), Right arm to left leg (lead 2). Left arm to left leg (lead 3).
When is a positive deflection?
when electricity is towards a positive.
When is a negative deflection?
when electricity is away from a positive
what is the isoelectic line
the invisible line of an ecg that everything returns to
which lead is the most positive and why?
lead 2 because overall wave of electricity is right atria to left venticle.
how fast does ecg paper travel
25mm per second
the tiny square on an ecg is how long?
0.04 seconds
5 tiny squares on an ecg are how long
0.2 seconds
time runs which way on ecg paper
across
What is a P wave
depolerisation of atria (positive)
How long should a P wave be?
0.08-0.12 seconds (2-3 squares)
What is the PR interval?
time between start of P wave and start of QRT complex
How long should PR be?
0.12-0.2 seconds (3-5 squares)
What hapens in the heart at PR
AV node holds electricity
QRS complex represents what?
ventricular depolarisation
How long should a QRS interval be?
0.04-0.12 seconds (1-3 squares)
Is Q positive or negative
negative
do ecgs need qr and s
no
What is the T wave measuring
ventricular repolarisation
Why is a T wave positive if its repolarisation?
see suzy
Why is QRS bigger than P?
over bigger area
QT intervals shorten when what happens?
heart rate increases
ST should always…
return to isoelectric line
U wave represents?
late repolarisation
Is a U wave normal?
yes but uncommon
What 10 things do you need to look at on an ECG
what is the heart rate? Is the heart rate regular? Are there P waves? Are P waves all the same size and shape? Is there a P wave before every QRS complex? Is there a QRS complex after every P wave? Is the PR interval normal? Is the QRS interval normal? Are the T waves normal? Is the ST segment iso-electric?
What preparation is needed for the patient?
expose as necessary, select are prepare electrode site (wipe if necessary), shave patient if necessary, attach leads to electrodes, attach electrodes to patient.
Where is the pacemaker in a normal ecg?
SA node
what is a normal ecg called?
normal sinus rhythm
What does PEA stand for
pulseless electrical activity
