ECG Flashcards
A wave of approaching depolarisation approaching an electrode causes
an upward going blip
When using standard limb leads, what events are transmitted better, fast or slow?
Fast
On an ECG, what causes the P wave?
Atrial depolarisation
On an ECG, what causes the QRS complex?
Ventricular depolarisation
On an ECG, what causes the T wave?
Ventricular repolarisation
The PR interval is mainly due to transmission through what?
The atrioventricular node (AV node)
QRS is equal to
the time for the whole ventricle to depolarise
The QT interval is
the time spent while ventricles are depolarised
Atrial repolarisation coincides with
ventricular depolarisation
Do different parts of the ventricle depolarise at the same or different times?
Different
The inter ventricular septum depolarises in what direction?
From left to right
The bulk of the ventricle depolarises from
the endocardial to the epicardial surface
Why is the T wave positive-going?
Action potential is longer in endocardial cells than in epicardial cells, so wave of repolarisation runs in opposite direction to wave of depolarisation
What would happen if the heart developed hypertrophy on the left or atrophy on the right?
Axis deviation
What extra information do the precordial leads give you?
Information on the same events but in the transverse plane
