Xtra Notes Flashcards
What does an ECG show
- change in voltage over time NOT ACTION POTENTIALS
On an ECG, how many seconds does each big square represent
0.2 seconds
On an ECG, how many milliseconds does each small square represent
40ms
On a 12 lead ECG, how many limb electrodes and chest electrodes are present
4 limb electrodes
6 chest electrodes
Give the septal electrode on an ECG
V1
Give the electrode on an ECG that reads the inferior aspect of the heart
Lead 2 and Lead 3
AVF and AVR
Give the electrode on an ECG that reads the lateral aspect of the heart
Lead 1
AVL
V5 and V6
Give the electrode on an ECG that reads the anterior aspect of the heart
V2, V3 and V4
Which ECG electrode sits in the 5th intercostal space at the midclavicular line
V4
On an ECG, where would the only negative P wave be found
AVR
How would you calculate the heart rate (ventricular rate) on an ECG
300/number of big squares between 2 QrS complex
Where would a normal QRS axis be between
AVL at -30 degrees
AVF at 90 degrees
How long is the PR interval on an ECG and what does it show
120 to 200 milliseconds
3 to 5 small squares
Conduction of wave of depolarisation from the AV node and His-Purkinje system
How long is the QRS complex on an ECG and what does it show
120 milliseconds (3 small squares) Ventricular depolarisation
What does the ST segment on an ECG represent
Interval between ventricular depolarisation and repolarisation
