All things ECG Reading Flashcards
What is happening during the P wave?
Contraction of the atria
What is happening during the QRS wave?
Ventricular depolarisation
What does the PR interval tell us?
The time taken for conduction through the AV node to the purkinje fibres.
Its the time between the onset of atrial depolarisation to onset of ventricular depolarisation
Whats the “normal” time for a PR interval to be?
0.12-0.20 seconds
What is represented by the ST segment?
End of ventricular depolarisation to the start of repolarisation
What does the T wave represent?
Ventricular repolarisation
Why do you have a dip in the Q wave before the QRS wave?
This is because the right atrium will receive the electrical impulse first and its depolarisation is moving away from the electrode, hence the downwards line. This is followed by the depolarisation of the left ventricle which is moving towards the electrode and so you have the upwards line.
What does the QT time interval tell us?
Total time for depolarisation and repolarisation of the ventricles to occur.
If you have a prolonged PR interval what does this indicate?
There’s a problem with the AV node
What is the normal range of the QRS complex?
<0.08-0.12 seconds
If you have a widened QRS complex what can this mean?
There’s a problem with the electrical activity in the ventricles of the heart
What is the normal range of the QT interval for males?
0.36-0.45 seconds
What is the normal range of the QT interval for females?
0.36-0.47 seconds
If a patient is tachycardic, what will this do to their QRS complex?
It will shorten their QRS complex
How do you calculate the cQT?
cQT= QT / (RR)^squareroot
