ECGs

Question 1

What electrodes make up aVL?

Answer 1

LA positive to RA and LL negative

Question 2

What causes the R wave?

Answer 2

ventricular walls depolarise

Question 3

What electrodes make up lead I?

Answer 3

RA negative to left arm positive

Question 4

Where is V1 located?

Answer 4

fourth intercostal space right sternal edge

Question 5

What electrodes make up lead III?

Answer 5

left arm negative to left leg positive

Question 6

What happens to the S wave from V1 to V6?

Answer 6

decreases

Question 7

Which limb is earthed for the standard limb leads?

Answer 7

right leg

Question 8

What does the PR interval represent?

Answer 8

time for the SA node impulse to reach the ventricles

Question 9

What does one large box represent?

Answer 9

0.2s and 5mm amplitude

Question 10

What does the QRS complex consist of in the chest leads?

Answer 10

an R wave followed by an S wave

Question 11

How do you calculate HR from an ECG with an irregular rhythm?

Answer 11

number of R-R intervals in 6s x 10

Question 12

How do you tell if there is left axis deviation?

Answer 12

I = positive and aVF = negative

Question 13

What is the position of the reference electrode in the augmented limb leads?

Answer 13

centre of the heart

Question 14

Which limb leads view the heart from the left?

Answer 14

I and aVL

Question 15

What electrodes make up aVR?

Answer 15

RA positive to LA and LL negative

Question 16

What is the normal duration of the QT interval?

Answer 16

0.44s in males and 0.46s in females (when adjusted for HR)

Question 17

What direction does lead II see the heart from?

Answer 17

anterior

Question 18

What does the P wave represent?

Answer 18

time for completion of atrial depolarisation

Question 19

What causes the T wave?

Answer 19

ventricular repolarisation spreads away from the recording electrode

Question 20

What electrode is always negative in the standard limb leads?

Answer 20

right arm

Question 21

Where is V4 located?

Answer 21

fifth intercostal space mid clavicular line

Question 22

How do you calculate HR from an ECG in sinus rhythm?

Answer 22

300/number of large squares between beats or number of large squares in R-R interval

Question 23

What electrodes make up aVF?

Answer 23

LL positive to RA and LA negative

Question 24

What is the duration of a normal PR interval?

Answer 24

0.12 - 0.2 s 3-5small squares

Question 25

How would you pick up stable angina?

Answer 25

exercise ECG - ST changes during and after exercise

Question 26

Which chest leads look at the interventricular septum from the right?

Answer 26

V1 and V2

Question 27

Where is V6 located?

Answer 27

same horizontal level as V4 mid-axillary line

Question 28

What causes the S wave?

Answer 28

ventricles at base of heart depolarise

Question 29

What does one small box represent?

Answer 29

0.04s and 1mm amplitude

Question 30

What electrodes make up lead II?

Answer 30

right arm negative to left leg positive

Question 31

What does the ST segment represent?

Answer 31

systole

Question 32

What electrode is always positive in the standard limb leads?

Answer 32

left leg

Question 33

What view of the heart do the chest leads provide?

Answer 33

horizontal

Question 34

How do you analyse an ECG?

Answer 34

1. verify patient details 2. check time and date ECG was taken 3. check calibration of the ECG paper 4. determine the axis if possible 5. workout rhythm 6. look at individual leads for voltage criteria changes or any ST or T wave changes

Question 35

Where is V2 located?

Answer 35

fourth intercostal space left sternal edge

Question 36

How do you tell if there is right axis deviation?

Answer 36

I = negative and aVF = positive

Question 37

Where is the reference electrode for the chest leads located?

Answer 37

centre of the heart

Question 38

Where is V3 located?

Answer 38

mid way between V2 and V4

Question 39

How would you pick up intermittent rhythm disturbances?

Answer 39

ambulatory ECG for 24 hrs or 7 days

Question 40

Where is V5 located?

Answer 40

same horizontal level as V4 anterior axillary line

Question 41

What is the PR interval?

Answer 41

start of the P wave to the start of the QRS

Question 42

What causes the Q wave?

Answer 42

ventricular depolarisation starts in the interventricular septum and spreads from left to right

Question 43

What causes an upward deflection on the ECG?

Answer 43

depolarisation moving towards the positive/recording electrode

Question 44

In which augmented limb leads are the waves negative?

Answer 44

aVR

Question 45

Which chest leads look at the anterior of the heart?

Answer 45

V3 and V4

Question 46

What does the TP segment represent?

Answer 46

diastole

Question 47

What is the normal QRS duration?

Answer 47

≤0.1s <3 small squares

Question 48

What lead is often used as the rhythm strip?

Answer 48

lead II

Question 49

What is the normal length of time for a P wave?

Answer 49

≤0.12s

Question 50

What causes a negative deflection on the ECG?

Answer 50

depolarisation moving away from the recording electrode

Question 51

What is the ST segment?

Answer 51

end of QRS to the start of the T wave

Question 52

Which limb leads view the heart from an inferior direction?

Answer 52

II, III and aVF

Question 53

What is the QT interval?

Answer 53

start of QRS to end of T wave

Question 54

What conditions can present with a normal ECG?

Answer 54

NSTEMI, intermittent rhythm disturbances, stable angina

Question 55

What provides the reference electrode for the chest leads?

Answer 55

standard limb leads linked together

Question 56

What causes the P wave?

Answer 56

atrial depolarisation spreads from SA node towards the recording electrode

Question 57

What does prolongation of the QT interval cause?

Answer 57

predisposition to arrhythmias

Question 58

Where are the electrodes positioned for the standard limb leads?

Answer 58

right arm, left arm and left leg

Question 59

Which chest leads look at the lateral aspect/left ventricle of the heart?

Answer 59

V5 and V6

Question 60

What happens to the R wave form V1 to V6?

Answer 60

increases

Question 61

How do you tell if there is extreme axis deviation?

Answer 61

I and aVF are both negative

Question 62

How do you tell if the axis is normal?

Answer 62

I and aVF are both positive

Question 63

Why is atrial repolarisation not visible on the ECG?

Answer 63

It occurs during the QRS complex so is masked