Normal ECG Flashcards
Define the normal P wave in the ECG ?
Represents(the wave of depolarisation)that spreads from the SA node throughout the atria
What does the normal P wave represent in the ECG ?
Atrial depolarisation
What is the duration of the normal P wave in the ECG in seconds and milliseconds?
0.08-0.1 seconds
80-100 ms
Define the isoelectric period after the P wave in the ECG ?
Represents the time in which the impulse is travelling within the AV node.
Define the normal PR interval in the ECG ?
Time from the onset of the P wave to the beginning of the QRS complex.
What is the duration of the normal PR interval in the ECG in seconds ?
0.12-0.20 seconds
What does the PR interval represent in the normal ECG ?
Represents the time between the onset of atrial depolarisation and the onset of ventricular depolarisation.
What does the QRS complex represent in the normal ECG ?
Ventricular depolarisation
What is the duration of the normal QRS complex in the ECG in seconds ?
0.06-0.1 seconds
Define the normal ST segment in the ECG ?
Is the isoelectric period following the QRS complex.
What does the normal ST segment represent in the ECG ?
- Represents period which the entire ventricle is depolarised(ventricular
depolarisation) . - Roughly corresponds to the plateau phase of the ventricular action potential.
What is the relationship between the ST segment and the ventricular action potential ?
Roughly corresponds to the plateau phase of the ventricular action potential.
What does the normal T wave represent in the ECG ?
Ventricular repolarisation.
What is the significance of the (small positive U wave) after the T wave in the ECG ?
Represents the last remnants of the ventricular repolarisation.
What does the normal QT interval represent in the ECG ?
Represents both of the ventricular depolarisation and repolarisation.
What is the relationship between the QT interval and the ventricular action potential ?
Roughly estimates the duration of an average ventricular action potential.
What is the duration of the normal QT interval in the ECG in seconds ?
0.2-0.4 seconds depending on heart rate.
What is the relationship between the duration of the normal QT interval and heart rate ?
The normal QT interval is 0.2-0.4 seconds depending on heart rate.
At high heart rate:-
1.ventricular action potential shortens in duration
2.Decrease in the QT interval
Define the normal RR interval in the ECG
It is between ventricular depolarisation.
Define the corrected QT interval ?
QT/Square root of the RR interval.
What is the significance of the corrected QT interval in the ECG ?
Assesses the QT interval that is independent on heart rate.
What is the normal duration of the normal corrected QT interval ?
0.44 seconds
