ECG Flashcards
When to undertake an ECG
chest pains
back pain
shortness of breath
falls
older people
woman complaining of chest pain
Abdominal/Epigastric pain
electrical burns
where are you placing limb electrodes
red lead goes to right shoulder
Yellow goes to left shoulder
Black goes to the right hip
Green goes to the left hip
What is lead one
aVR
What is lead two
aVL
What is lead three
aVF
Why is it that we mostly look at lead 2
it follows the conduction of the heart
What is the p wave
Atrial depolarisation
What is the QRS wave
ventricles depolarisation
What is the t wave
Ventricular repolarisation
what are the limb lead views
Lead 1 looks towards the left aspect of left ventricles
lead 2 looks towards the inferior portion of the heart LV
lead 3 looks towards the inferior left and Right ventricles
aVr looks at the right upper portion of the heart
aVL: looks towards the left upper portion of the heart.
aVF: looks towards the inferior portion of the heart.
What does the ecg print at
prints at 25 mm per second
5 big squares = 25 mm = 1 sec
30 big squares = 6 sec
5 small square = 5mm =0.2 sec or 200 ms
1 small square = 1mm =0.04 sec
PR intervals
PR interval start of atrial depolarization to the start of ventricle depolarization 3 - 5mm
QT interval
Is the start of ventricle depolarisation to the end of ventricular repolarisation 11mm in men 11.5mm in woman
ST seagment interval
end of ventricular depolarisation to the start of ventricular repolarisation
RR interval
bewteen each complex
QRS interval
2 - 2.5 mm
What are the different types of ventricle complexes
q wave = first negative deflection
r wave = first positive deflection
s wave = deflection following q wave
how to calcualte heart rate
300 divided by the number of big sqaures within PR interval.
chest leads placement
v1 - 4 intercostal space right
v2 - 4 intercostal space left
v3 - bewteen v2 and v4
v4 -5 intercostal space mid clavicular line
v5 - bewteen v4 and v6
v6 - mid axillar line
what are the 10 rules of ecg the first rule
1.The pr interval bewteen 0.12 & 0.2 sec 3-5 small squares
what are the 10 rules of ecg the second rule
The QRS duartion is ^ 0.11 sec 3 small sqaures
what are the 10 rules of ecg the third rule
The QRS complex should be predominately upheld upright in leads 1 & 2
what are the 10 rules of ecg the fourth rule
QRS &T waves tend to have the same general direction in the limb area
what are the 10 rules of ecg the fifth rule
Confirm that aVR is negative
what are the 10 rules of ecg the sixth rule
The R wave in the precordial leads must grow from v1 to at least v4
what are the 10 rules of ecg the seventh rule
The ST segment should start isoelectric except in v1 and v2 where it may be slightly elevated
what are the 10 rules of ecg the eight rule
The P wave should be upright in 1,2,v2 to v6
what are the 10 rules of ecg thet nineth rule
There should be no Q waves - 0.04 sec 1 small sqaure in width in 1,2,v2 to v6
what are the 10 rules of ecg the first rule
The T wave must be upright in 1,2,v2 to v6
What are the guidelines on Stemi
to have 1mm in two leads with st segment elevation either I & aVL or II & III or V2 - V4
≥ 2.5 mm in men < 40 years (V2 & V3),
≥2 mm in men ≥ 40 years (V2 & V3),
≥ 1.5 mm in women (V2 & V3)
or
≥ 1 mm in all other leads (except V4/7/8/9)
What is a anterior STEMI
ECG changes include ST elevation in V1 – V4
Reciprocal changes in inferior leads
what is inferior STEMI
ECG changes include ST elevation in II, III & aVF
Reciprocal changes in aVL and sometimes I. but in inferior u need to do a V4R.Move V4 to the right hand side (5th intercostal space (right) mid clavicular).
ST segment elevation of 0.5mm or more is positive. This indicates an Inferior MI with Right Ventricular Involvement.
What is a lateral STEMI
CG changes include ST elevation in 1, aVL, V5 – V6.Reciprocal changes in inferior or anterior leads.Vasculature affected is the Circumflex (or LCA)
What is 1st degree heart block
PR interval > 200 ms (> 0.2 seconds or > 5 mm).Does not cause symptoms
Caused by delay to AVN transmission, due to following:
Increased vagal tone,Ischaemia ,Athletic heartt,AVN blocking drugs
What is 2nd degree heart block: type 2
Intermittent non-conducted P waves.PR interval does not increase.Failure of the conduction system caused by structural damage, e.g. necrosis.Also caused by electrolyte imbalance, surgery, medications.
More likely to be haemodynamically unstable and transition into complete HB, asystole/ SCA.
What is 2nd degree heart block type 1
Prolongation of PR interval until a QRS is dropped.Usually does not cause haemodynamic instability
Due to AVN suppression (fatigued AV Nodal cells or increased vagal tone)
Other causes include medications, inflammation, ischaemia and surgery
