The normal ECG Flashcards
(21 cards)
Definition of the Q wave
The first deflection of the QRS complex if it is downward
Definition of R wave
The first upward deflection
Definition of R-prime (R’)
The second upward deflection (if present)
Definiton of S wave
First downward deflection following an upward deflection
Definition of QS wave
If the entire QRS is one downward deflection
In which Leads is Q wave normal?
What is the normal amplitude of the Q wave?
Lateral leads (AvL, I, V5, V6) - represents septal depolarization
Normal amplitude should be max 0.1 mV
What is the difference between segments and intervals?
Interval = wave + segment
Which leads are the inferior leads?
Lead II, III, AvF (60, 120, 90 degrees)
Which leads are the lateral leads?
Lead I, AvL(0, -30), V5, V6
Which lead is the right sided?
AvR (-150) V1
Which leads are anterior?
V2, V3, V4
What is the normal duration of the PR interval?
0.12 - 0.2 s
What is R wave progression?
Progressivly increasing R amplitude from V1 to V5
V6 is normally a little smaller than V5
How long is the normal QRS interval?
0.06s - 0.1 s
In which leads should the T wave be positive?
It is typically positive in leads with a tall R wave
What is the typical length of the QT interval?
It normally composes 40% of the cardiac cycle.
What is the normal QRS amplitude?
10mV in chest leads
5mV in limb leads
How can you see if the rhytm is from the sinus node?
positive QRS in leads I and II, negative in AvR
What is the normal heart axis?
90 to -30 degrees (pos QRS in lead I, II)
What is the normal duration and amplitude of the P wave?
less than 0.12s and max 2,5mm
What is the easiest way to calculate heart rate on ECG?
300 divided by number of large squares pr cycle
or
1500 divided by number of small squares pc cycle
