ECG (electrocardiogram)

Question 1

what does ECG stand for?

Answer 1

electrocardiogram

Question 2

what does an ECG show?

Answer 2

• records the electrical activity of the heart
• shows the rhythm and rate of your heart
• can indicate future health risks (heart attacks etc)

Question 3

what are the 3 main aspects of a heartbeat?

Answer 3

1- p wave (atrial depolarisation)
2- QRS complex (ventricular depolarisation)
3- T wave (ventricular repolarisation)

Question 4

explain the p wave

Answer 4

the p wave is the start of the heartbeat, originates in the SA node (pacemaker of the heart), it shows the atrial depolarisation or the contraction if the atrias (top two chambers of the heart) more positive!!!!

Question 5

explain the QRS complex

Answer 5

the QRS complex is the ventricular depolarisation (contraction of the ventricles) 0.06-0.12s- more positive!!!!!

Question 6

explain the T wave

Answer 6

the T wave is the repolarisation the ventricles or the recovery phase- becomes negative!!!!

Question 7

list the steps that the electrical impulse travels along

Answer 7

1-SA node (natural pacemaker of the heart) 60-100BPM
2-AV node- 40-60BPM
3-Bundle of His- 40-60BPM
4-Left and right bundle branches- 20-40BPM
5-Purkinje fibres- 20-40BPM

Question 8

how to interpret the ECG?

Answer 8

1. check the distance between the R’s (large peak) see if they’re all the same distance apart- check rhythm
2. check the p wave is present and upright
3. measure the PR interval- 0.12s-0.20s
4. measure QRS complex- 0.06-0.12s
5. calculate heartbeat- how many large squares in 6 second strip? x0.04s

Question 9

how many seconds does a large square indicate?

Answer 9

0.20s

Question 10

how many seconds does a small square indicate?

Answer 10

0.04s

Question 11

how many small squares are there in one large square?

Answer 11

5 - 0.04 x 5 = 0.2s

Question 12

How do you tell if there is a normal R wave progression through V1 to V6?

Answer 12

Poor R wave progression refers to the absence of the normal increase in size of the R wave from v1 to v6. In v1 the R wave should be small, the R wave becomes larger throughout the leads from v1 to v6. R wave should be larger than the S wave in lead v4.

Question 13

Is the width and height of the p wave normal?

Answer 13

The p wave should be roughly 0.12 s, a height of nearly 3mm.