Principles of Electrocardiography Flashcards
1
Q
- What is an electrocardiogram (ECG)?
A
- Recording of the electrical activity of the heart (and other muscles).
2
Q
- Outline very simply how an ECG works
A
Sensors attached to the skin are used to detect signals produced by the heart each time it beats.
3
Q
- Name the axis of the graph produced by an ECG
A
voltage vs time
4
Q
- What is a galvanometer?
A
(an instrument used to measure the size & direction of small electric currents)
5
Q
- What is a dipole?
A
where there is a difference in charge between one bit of membrane and another
6
Q
- When all of the heart muscle is polarised (E.g. at rest), is there a dipole or not?
A
there is no dipole
7
Q
- When part of the heart muscle is depolarised, is there a dipole or not?
A
a dipole exists
8
Q
- When all of the muscle is depolarised (E.g. contracting), is there a dipole or not?
A
there is no dipole
9
Q
- What does 12 ECG leads allow?
A
Looking at the heart from 12 angles
10
Q
- What is ventricular ectopics?
A
Premature ventricular contractions
11
Q
- Where does Type 1 2nd degree heart block occur?
A
- It occurs in the AV node above the bundle of his
12
Q
- What is Type 1 2nd degree heart block?
A
P-R interval progressively longer until a P wave is blocked. Cycle begins after blocked P wave.
13
Q
- What is sinus tachycardia?
A
- Sinus rhythm is faster than 100bpm but usually not faster than 130bpm. Conduction is normal.
14
Q
- What is sinus bradycardia?
A
- Slowed sinus rhythm (lower than 60bpm but not lower than 40) but normal conduction.
15
Q
what causes a prolonged QRS complex
A
bundle branch blocks
