ECG Flashcards
What are the chest leads?
V1-V6
What are the limb leads? Which ones are bipolar?
I, II, III, aVR, aVL, aVF
I, II and III are bipolar
Inferior leads?
II, III, aVF
Anterior leads?
V1-V4
Lateral leads?
V5, V6, I, aVL
Where are the limb leads and chest leads and rhythm strip on the reading?
Limb leads on the left, chest leads on the right, rhythm strip on the bottom.
Which is the rhythm strip if there isn’t actually a rhythm strip?
II and V1
What does P wave correspond to?
Atrial depolarisation/contraction
What is the PR interval?
Distance between P wave and QRS complex
What does QRS complex correspond to?
Ventricular contraction (QRS complex hides atrial relaxation
What does T wave correspond to?
Ventricular relaxation
What is the QT interval?
Distance between Q wave and T wave
First things you do when interpreting ECG?
Patient name, DoB and symptoms.
ECG date and time.
Check calibration: paper speed (25mm/s), 1mV calibration (at start of trace) - 2 large squares in height.
How do you work out rate?
Number of small sqaures in one R-R interval - divide this into 300.
Rate if RR interval = 3 squares?
100bpm
Rate if RR interval = 4 squares?
75bpm
Rate if RR interval = 5 squares?
60bpm
How to work out rhythm?
Mark 4 R peaks on piece of paper and move along trace to confirm consistency.
What are you looking for to confirm sinus rhythm?
Regular normal P waves before each QRS complex
No clear P waves and irregular QRS = ?
AF
Leads for axis?
I and II
QRS complexes in I and II are both predominantly…?
Positive
If I and II R waves point away from each other?
LAD (Legs apart)
If I and II R waves point towards each other?
RAD
Cause of left axis deviation?
Heart conduction defects
Cause of right axis deviation?
RVH
What are looking for in P waves?
Are P waves present?
Do they occur regularly?
Does a P wave precede each QRS complex?
Do the P waves look normal? (Smooth, rounded and upright?)
What should the height of the P wave be?
What do bifid P waves indicate?
P Mitrale - left atrial hypertrophy (mitral stenosis)
What does peaked P waves indicate?
P Pulmonale (right atrial hypertrophy)
How long should the PR interval be?
3-5 small squares (0.12-0.2 seconds)
What does a prolonged PR interval indicate?
Heart block
What does a reduced PR interval indicate?
Accessory conduction pathway (Wolff-Parkinson-White Syndrome)
Where should you look when looking at the QRS complex?
Rhythm strip
Width of QRS complex?
3 small sqaures (0.12 seconds)
If QRS complex longer than 0.12 seconds…?
Complex originated in the ventricles
If QRS complex shorter than 0.12 seconds…?
The complex is supra-ventricular in origin
Where do you look for bundle branch block?
V1 and V6
QRS in V1 has M pattern and QRS in V6 has W pattern…?
RBBB (MaRRoW)
QRS in V1 has W pattern and QRS in V6 has M pattern?
LBBB (WiLLiaM)
Where do you look for R wave progression?
Chest leads (V1-V6)
What is R wave progression?
QRS complexes should progress from mostly negative in V1 to mostly positive in V6
Where should you check the ST segment?
All leads
What constitutes significant elevation or depression?
> 1 small square
Main cause of ST elevation?
MI
Main cause of ST depression?
Ischaemia
Where should you check the T waves?
All leads
Where is T wave inversion normal?
aVR, V1 (right leads)
What does T wave inversion indicate?
Ischaemia/Post-MI
What do tented T waves indicate?
Hyperkalaemia
What do flat T waves indicate?
Hypokalaemia
Typical pattern in PE?
an S1Q3T3 pattern - a prominent S wave in lead I, a Q wave and inverted T wave in lead III
SINUS TACHY
