ECG Flashcards
What is an ECG?
A representation of the electrical events of the cardiac cycle.
What does P wave represent?
Atrial Depolarisation (atrial contraction)
What does PR interval represent?
Delay at the AV node.
Time taken for impulse to travel from atria, through AV node, to the ventricles
What does QRS complex represent?
Ventricular depolarisation (Ventricular contraction)
What does T wave represent?
Ventricular repolarization
What does QT interval represent?
Entire duration of ventricular electrical activity.
How to calculate Heart Rate?
Standard Method: Count number of R waves in a 6-second strip and multiply this number by 10
300 Rule: (for regular rhythms), divide 300 by number of large squares between R waves
How to know whether rhythm regular/irregular?
Regular rhythm: R-R intervals are consistent
Irregular rhythm: R-R intervals vary
True/False
If P waves are present, regular, and found before each QRS complex, this means it is a normal sinus rhythm.
True
What does prolonged PR interval mean?
1st degree heart block. (AV block)
Suggest ECG finding for:
Irregular rhythm with no distinct P waves
Atrial Fibrillation
Suggest ECG finding for:
Sawtooth pattern of P waves
Atrial flutter
Suggest ECG finding for:
Wide QRS complexes with a regular rapid rhythm (more than 100 beats/min)
Ventricular Tachycardia
Suggest ECG finding for:
No P wave, no QRS complex, no T wave seen.
Rate, rhythm cannot be determined, irregularly irregular rhythm
Ventricular fibrillation
Suggest the type of AV block in this pattern:
Regular rhythm
Uniformly prolonged PR interval
1st degree AV block
Suggest the type of AV block in this pattern:
Irregular rhythm
Progressive PR interval prolongation until QRS missing
2nd degree AV block, Mobitz Type I
What does T wave inversion indicate?
Ischaemia
What is seen in ECG for a patient with Left Ventricular Hypertrophy (LVH)?
Tall R waves in lead V5/V6
Deep S waves in lead V1/V2
Describe ECG finding in 2nd degree AV block, Mobitz Type II.
Irregular rhythm.
PR interval may be normal or prolonged, BUT is Constant! and fixed!
Unexpected blocked P waves, don’t know when QRS drops
Describe ECG for a 3rd degree AV block.
P wave and QRS complex march out separately (no pattern/relationship).
Some QRS bizarre.
PR interval constantly changing.
