ECG MED ED Flashcards
Where do the limb electrodes go?
Red: right arm (forearm or wrist)
Yellow: left arm (forearm or wrist)
Green: left leg (proximal to ankle)
Black: right leg (proximal to ankle)
Where is V1 placed?
4th intercostal space, right sternal edge
Where is V2 placed?
4th intercostal space, left sternal edge
Where is V3 placed?
midway between V2 and V4
Where is V4 placed?
5th intercostal space, mid-clavicular line
Where is V5 placed?
Anterior axillary line in straight line with V4
Where is V6 placed?
mid-axillary line straight line with V4 and V6
What should you avoid with sticking on electrodes?
hair
What do you check with ECG?
- NAME, DOB, TIME TAKEN
- Rate and Rhythm
3.
What is the first thing to check on ECG?
CHECK NAME, DOB and TIME TAKEN
What is the normal paper speed?
should be 25mm/sec
How long is one small square?
1mm = 0.04 sec
How long is one big square?
5mm = 0.20sec
What is the normal calibration?
should be 1cm (10mm)/mV
How do you check the calibration signal?
should move two big squares (rectangle at the end should be 2 sqaures tall)
What angle does lead III show?
120 degrees
What angle does aVF show?
90 degrees
What angle does lead II show?
60 degrees
What angle does lead I show?
0 degrees
What angle does aVL show?
-30 degrees
What angle does aVR show?
-150 degrees
What do leads I and aVL look at?
left side of heart
What do leads III, aVF and II look at?
inferior aspect of heart
What do leads V1 and V2 look at?
septal
What do leads V3 and V4 look at?
anterior of heart
What do leads V5 and V6 look at?
lateral left side of heart
How do you determine the rate?
count QRS complex in rhythm strip x 6
What is normal rate?
Normal range is 60-100bpm
What are the 3 types of rate?
- normal
- tachycardic
- bradycardic
What are the 3 types of rythm?
- sinus
- regular irregular
- irregular irregular
What is sinus rhythm?
P wave starting each QRS
What is a regular irregular rhythm?
consistent gap between QRS
What is an irregular irregular rhythm?
change gap between QRS
Which leads are used to assess cardiac axis?
leads I, II, aVF
What is the cardiac axis if II is +ve and I is +ve?
normal
What is the cardiac axis if II is -ve and I is +ve?
left axis deviation
What is the cardiac axis if II is +ve and I is -ve?
right axis deviation
What is the cardiac axis if aVF is -ve and I is -ve?
extreme axis deviation
How can you tell if QRS is +ve or -ve?
for something to be -ve or +ve then the great half of QRS will be above or below isoelectric line
What is a way to remember left axis deviation?
I and II LEAVING eachother
What is a way to remember right axis deviation?
leads I and II RETURNING to eachother
What do P wave’s represent?
first deflection: atrial depolarisation
What are the features of P waves?
- Should precede every QRS complex
2. Should be smooth
How long should P waves be?
<0.12s (<3 small squares)
How could p waves vary?
- Long
- Short
- Absent
- Biphasic
- Inverted
What is P pulmonale related to?
right atrial dilation (pulmonary stenosis can be a cause)
What is P mitrale related to?
left atrial dilation – second hump (mitral stenosis can be a cause)
What is the defintion of the PR interval?
start of P wave to start of QRS complex
How long should the p wave be?
0.12-0.20secs (3-5 small squares - max one big box)
What does the PR interval represent?
time between SAN node depolarisation to AV node depolarizations
What should the PR interval be?
isoelectric
How can the PR interval go wrong?
- Prolonged
- Not flat
- Short
How long should the QRS be?
- Should be narrow <0.12s (less than 3 small squares)
2. Shouldn’t be too big/small
How can you tell if QRS complex is too big/small?
S wave depth in V1 and tallest R wave in V5/6 should be <35mm
How does the QRS complex act as a transition point?
transition point to negative to positive between V3 and V4 (as usually negative in V1,V2 and very positive in V5 and V6) – and if not the case, poor R wave progression
How can the QRS complex go wrong?
- Wide QRS complex
2. Absent: cardiac arrest
What is it called when there is alternating bigger and smaller QRS?
electrical alternans
How can you tell poor R wave progression?
V5 and V6 QRS still negative
If the QRS is too big what may this suggest?
left ventricular hypertrophy
What is the J point?
region where QRS complex becomes ST segment
What is the J point usually?
- should normally be isoelectric
- some patients have raised J point as a normal variant
What can happen to the J point?
can be raised or lowered can help see ST segment elevation and depression
What is an osborne wave?
(straight after QRS): hypothermia
What is an ST segment?
bit between QRS complex and T wave
What should the ST segment be usually?
isoelectric
What does the ST segment represent?
pause between ventricular depolarisation and repolarisation
How can the ST segement change?
- Elevated
- Depressed
- Morphology
What must you include with ST segment change?
- Flat elevation
- Upsloping
- Downsloping
- Convex
- Concave
What is the T wave?
usually last deflection of heart cycle
What should the T wave be usually?
be positive in all leads except aVR and V1
How big is the T wave normally?
- Fairly small:
1. <5mm in limb leads
2. <10mm in praecordial leads
3. Should be smaller than QRS
What could go wrong in the T wave?
- Inverted
- Taller/tented
- Flattened
- Biphasic
What do you need to say with biphasic T wave?
(starts inverted or upright make it clear!)
What is a U wave?
Waveform after the T wave
What does the U wave suggest?
usually pathological but can be normal (easier to see in bradycardia) – young fit athletic person can be normal in
What is the normal size and direction of the U wave?
- Usually same direction as T wave
2. 1/4 size of T wave
What does the U wave represent?
Could represent repolarisation of Purkinje fibres
What are possible issues with U waves?
- Obvious U waves
2. Inverted U waves, opposite direction to T wave (indicates heart disease often)
What is the QT interval?
from start of QRS to end of T wave
What is the normal QT interval?
- QTc <0.44s in men and <0.46s in women
2. QTC>35s
What does the QT interval vary with?
with HR; gets shorter at faster HR, longer at slower HR – therefore needs to be corrected for heart rate (hence the c).
How can you QT be wierd and why?
- Long (hypocalcaemia, drugs and genetic syndrome)
2. Short (hypercalcaemia)
