Basic ECG reading reqs

Question 1

What is the standard P wave morphology?

Answer 1

• P wave should have a rounded upright shape in Lead II. - Has a normal duration of 0.08 – 0.10s =or2-2.5 small squares.

Question 2

Why should the PR interval match the isoelectric baseline?

Answer 2

• It represents a period of electrical inactivity.

Question 3

Why is the time period of the PR interval relevant?

Answer 3

• It showing the allowance of atrial contraction to complete ventricular filling before the process of ventricular contraction occurs.

Question 4

What is the normal duration of the PR interval?

Answer 4

• The duration of the PR interval is 0.12 -0.20s or 3-5 small squares.

Question 5

How many wave forms make up the QRS complex?

Answer 5

• The QRS complex is a collection of 2, possibly 3 waveforms.

Question 6

What is the Q wave defined as on the ECG strip?

Answer 6

• The Q wave is defined as the first negative deflection following the PR interval.

Question 7

What is the R wave defined as on the ECG strip?

Answer 7

• The R wave is defined as the first positive deflection after the PR interval.

Question 8

Why is the peak of the QRS complex much taller than that of the P wave?

Answer 8

• As there is much more ventricular muscle being depolarized.

Question 9

What is the normal duration of the QRS complex?

Answer 9

• The normal duration of the QRS complex is 0.06 -0.12s or 1-3 small squares.

Question 10

What is the difference between an interval and a segment?

Answer 10

• An interval includes at least one of the wave forms it mentions e.g. the PR interval includes the duration of the P wave. - A segment goes from the end of one wave form to the beginning of the next.

Question 11

What does the ST segment represent?

Answer 11

• The end of the QRS complex (end of ventricular depolarization and the beginning of the T wave (Start of the ventricular repolarization).

Question 12

If the ST segment is not on the Isoelectric line, what does it represent?

Answer 12

• If the ST segment is not on the isoelectric line, it represents abnormal ventricular repolarization.

Question 13

What are the total components of a normal rhythm strip?

Answer 13

• An upright P wave. And duration of 0.08 – 0.10s =or2-2.5 small squares. - A PR interval of between 0.12-0.2s or 3-5 small squares - A QRS with no Q has a duration of 0.08-0.12s or 1-3 small squares - An ST segment that follows the isoelectric baseline from the end of the QRS to the start of the T wave. - An upright T wave.

Question 14

What considers a rate to be Tachycardic?

Answer 14

• Arbitrarily any rhythm faster than 100 beats/min

Question 15

What considers a rate to be Bradycardic?

Answer 15

• Arbitrarily any rhythm slower than 40 or 50 beats/min.

Question 16

What is the inherent rate of the SA node?

Answer 16

• Sino Atrial (SA) node: 60-100 beats/minutes.

Question 17

What is the inherent rate of the AV node?

Answer 17

• Atrioventricular rate (AV) node: 40-60 beats/minute.

Question 18

What is the inherent rate of the Purkinje Fibres?

Answer 18

• Purkinje Fibres rate: 20-30 beats/minute.

Question 19

What are the two most popular methods for calculating a rhythm rate?

Answer 19

• The 6 second and 300 method.

Question 20

How to you calculate the rate based on the 6 second method?

Answer 20

• You calculate the number of R waves in the six second strip. - Multiple the above number by 10 and that is your estimated rhythm.

Question 21

How do you calculate the rate based on the 300 method?

Answer 21

• Firstly, find an R wave that falls exactly on the heavy grid line. - Then count the grid lines until the next R wave, 300, 150, 100, 75, 60, 50.