ECG Flashcards
(21 cards)
What does the P wave represent?
Atrial Depolarisation
How long should the P wave be? How much deflection should it cause?
0.10 seconds or less, 0.5 - 2.5 mV
What is the standard speed for an ECG to be recorded at?
25mm per second
At 25mm/sec how long does one small (1mm) and one large box (5mm) represent?
0.04 seconds and 0.2 seconds
What does the QRS complex represent?
Ventricular Depolarisation
How long should the QRS complex be on a ECG?
0.08 - 0.12 seconds (2-3 small boxes)
What does the T wave represent?
Ventricular repolarisation
Which way should the T wave deflect?
The same way as the QRS complex. Both should be a positive deflection on lead II
What is the inherent firing rate of the SA node?
60-100bpm
What is the inherent firing rate of the AV node?
40-60bpm
What is the inherent firing rate in the bundle branches or purkinje fibres?
less than 40bpm
What is the PR segment?
the END of the P wave to the beginning of the QRS complex
What is the ST segment?
the END of QRS to BEGINNING of T wave
Where is the J point?
The start of the ST segment, where the QRS complex ends
What is the TP segment?
the END of T wave to the START of P wave
What is the PR interval?
START of P to START QRS
What is the QT interval? What does it represent?
START QRS to END T
Depolarisation and repolarisation of the ventricles
How long should the PR interval be?
0.12 - 0.2 secs (3 - 5 small boxes)
How long should the RR interval be?
0.6 - 1.0 seconds (3 - 5 large boxes)
How long should the QT interval be?
0.4 - 0.43 seconds (10 - 11 small boxes)
What is the 8 step method for assessing an ECG?
- Determine the rate
- Determine the rhythm
- Identify and analyse the P wave
- Determine the PR interval, the AV conduction ratio
- Identify and analyse the QRS complexes
- Determine origin of electrical activity
- Identify dysrhythmia
- Assess the clinical significance of the rhythm
