ECG

Question 1

What does a lead do?

Answer 1

Measures difference in potential at two points

Question 2

Where does lead I go?

Answer 2

RA -ve to LA +ve

Question 3

Where does lead II go?

Answer 3

RA -ve to LL +ve

Question 4

Where does lead III go?

Answer 4

LA -ve to LL +ve

Question 5

What does depolarisation towards the electrode cause?

Answer 5

Upward deflection in the ECG

Question 6

What does depolarisation away from the electrode cause?

Answer 6

Downward deflection in the ECG

Question 7

Which limb leads are bipolar?

Answer 7

Standard

Question 8

Which limb leads are unipolar?

Answer 8

Augmented

Question 9

What is the polarity of the augmented limb leads?

Answer 9

One positive electrode with the two others linked as negative

Question 10

What is important to remember about aVR?

Answer 10

It is always inverted

Question 11

Which plane do the chest leads work in?

Answer 11

Axial

Question 12

How many electrodes are in a 12 lead ECG?

Answer 12

9

Question 13

What does the ST segment correspond to?

Answer 13

Systole- ventricles contract

Question 14

What does the TP segment correspond to?

Answer 14

Diastole- ventricles relax

Question 15

What would be the next test to do in suspected intermittent rhythm disturbance?

Answer 15

Ambulatory ECG for 12 hours or 7 days

Question 16

What would be the next test to do for stable angina?

Answer 16

Exercise ECG

Question 17

Where should V1 be placed?

Answer 17

4th IC space, right sternal angle

Question 18

Where should V2 be placed?

Answer 18

4th IC space, left sternal angle

Question 19

Where should V3 be placed?

Answer 19

Halfway between V2 and V4

Question 20

Where should V4 be placed?

Answer 20

Apex beat- 5th intercostal space midclavicular line

Question 21

Where should V5 be placed?

Answer 21

Anterior axillary line

Question 22

Where should V6 be placed?

Answer 22

Mid axillary line

Question 23

How long does one large box correspond to?

Answer 23

0.2 secs

Question 24

How long does one small box correspond to?

Answer 24

0.04 secs

Question 25

What does the p wave represent?

Answer 25

Atrial depolarisation

Question 26

What does the PR interval represent?

Answer 26

AV nodal delay

Question 27

What does the QRS complex represent?

Answer 27

Ventricular depolarisation

Question 28

What does the t wave represent?

Answer 28

Ventricular repolarisation

Question 29

What does the QT segment correspond to?

Answer 29

Depolarisation and repolarisation of the ventricles

Question 30

How long should the QT segment last?

Answer 30

0.36-0.44 secs

Question 31

How long should the p wave last?

Answer 31

0.08-0.1 secs

Question 32

How long should the PR interval be?

Answer 32

0.12-0.1 secs

Question 33

How long should the QRS complex last?

Answer 33

<0.1 secs

Question 34

How do you calculate the heart rate with a regular rhythm?

Answer 34

300/no of large squares between beats

Question 35

How do you calculate the heart rate with an irregular rhythm?

Answer 35

The number of QRS complexes in 30 large squares and multiply by 10

Question 36

What is step 1 of analysing an ECG?

Answer 36

Verify patient name and DOB

Question 37

What is step 2 of analysing an ECG?

Answer 37

Check date and time ECG was taken

Question 38

What is step 3 of analysing an ECG?

Answer 38

Check the calibration of the ECG paper

Question 39

What is step 4 of analysing an ECG?

Answer 39

Determine the axis

Question 40

What 7 things are involved in analysing the rhythm of an ECG?

Answer 40

``` Is electrical activity present? Is the rhythm regular or not? What is the heart rate? Are p waves present What is the PR interval? (normally 3-5 small squares) Is each p wave followed by a QRS? Is the QRS duration normal? ```

Question 41

What is step 6 of analysing an ECG?

Answer 41

Look at individual leads for voltage criteria changes and ST/t wave changes

Question 42

What suggests a normal ECG axis?

Answer 42

Complexes in lead I and II which are both positive

Question 43

What suggests left axis deviation?

Answer 43

-30 to -90 degrees

Question 44

What suggests right axis deviation?

Answer 44

+90 to +180 degrees

Question 45

What can cause left axis deviation?

Answer 45

LVH, inferior MI, VT from LV focus, WPW sometimes

Question 46

What can cause right axis deviation?

Answer 46

RVH, anterolateral MI, some WPW, PE

Question 47

What lead changes suggest an inferior MI?

Answer 47

II, III, aVF

Question 48

What lead changes suggest an anteroseptal MI?

Answer 48

V1-4

Question 49

What lead changes suggest an anterolateral MI?

Answer 49

V4-6, aVL

Question 50

What lead changes suggest a posterior MI?

Answer 50

tall R and and ST depression in V1-2

Question 51

What artery is involved in an inferior MI?

Answer 51

Right coronary

Question 52

Which artery is involved in an anteroseptal MI?

Answer 52

Left anterior descending

Question 53

Which artery is involved in a posterior MI?

Answer 53

Circumflex

Question 54

What can cause ST depression and inverted T waves in V5-6?

Answer 54

Digoxin effect

Question 55

What can cause tall, tented T waves, widened QRS and absent p waves?

Answer 55

Hyperkalaemia

Question 56

What can cause small T waves and prominent U waves?

Answer 56

Hypokalaemia

Question 57

What can cause a short QT interval?

Answer 57

Hypercalcaemia

Question 58

What can cause a long QT interval and small T waves?

Answer 58

Hypocalcaemia

Question 59

What do both types of bundle branch block cause?

Answer 59

Delayed conduction and hence prolonged QRS

Question 60

What can be seen on an ECG of right bundle branch block?

Answer 60

Inverted T waves in V1-3/4 and a deep wide S wave in V6

Question 61

What can be seen on an ECG of left bundle branch block?

Answer 61

M pattern in V5, inverted T waves in I, aVL and V5-6

Question 62

What are causes of right bundle branch block?

Answer 62

Isolated, PE, cor pulmonale

Question 63

What can cause left bundle branch block?

Answer 63

IHD, hypertension, cardiomyopathy, idiopathic fibrosis