ECG

Question 1

What is meant by a 12-lead ECG?

Answer 1

V1-V6 precordial leads

3 limb leads (LA, RA, LL)

Question 2

Where are the precordial leads placed on the chest?

Answer 2

V1: 4th ICS, right side
V2: 4th ICS, left side
V3: between V2 and V4
V4: 5th ICS, left mid-clavicular line
V5: 5th ICS, left anterior axillary line
V6: 5th ICS, left mid-axillary line

Question 3

What do the limb leads represent?

Answer 3

Lead 1: RA to LA (LA = recording electrode)
Lead 2: RA to LL (LL = recording electrode)
Lead 3: LA to LL (LL = recording electrode)

Question 4

What are the augmented limb leads?

Answer 4

AVR (right arm in reference to other two leads)
AVL (left arm in reference to other two leads)
AVF (left leg in reference to other two leads)

Question 5

What leads are looking at the inferior heart?

Answer 5

Leads 2,3, AvF

Question 6

What leads are looking at the lateral heart?

Answer 6

1, AvL, V5, V6

Question 7

What leads are looking at the anterior heart?

Answer 7

V1-V6

Question 8

What time frame does a big box represent?

Answer 8

0.2 seconds

Question 9

What time frame does a small box represent?

Answer 9

0.04 seconds

Question 10

How many boxes on an ECG are in one second?

Answer 10

5 big boxes

Question 11

How do you calculate a regular heart rate?

Answer 11

300/R-R

Question 12

How do you calculate an irregular heart rate?

Answer 12

Number of QRS in 30 x 10

Question 13

What is meant by a normal heart axis?

Answer 13

Electrical direction of the heart is between -90 and +30 degrees

Question 14

How do you know a heart axis is normal?

Answer 14

Lead 1 (at -30) and aVF (at +90) are both upright (positive)

Question 15

In left axis deviation, what happens to the leads?

Answer 15

Lead 1 is positive

aVF is negative

Question 16

In right axis deviation, what happens to the leads?

Answer 16

Lead 1 is negative

aVF is positive

Question 17

What is a normal PR interval?

Answer 17

0.12s-0.2s

Roughly 3-5 small boxes from start of P to QRS

Question 18

What is a normal QRS?

Answer 18

<0.1s

Roughly two and a bit boxes

Question 19

Define sinus rhythm

Answer 19

Normal P waves followed by a QRS

Question 20

List the key steps to analysing an ECG

Answer 20

1. Name, DoB
2. Calibration
3. Electrical activity?
4. Regular or irregular?
5. Heart rate?
6. P waves? PR interval?
7. P wave followed by QRS? QRS normal?
8. Axis of the heart
9. Other leads

Question 21

What medication can be used to differentiate between SVT and VT?

Answer 21

Adenosine

Question 22

What is the acute treatment for an MI? (mnemonic!)

Answer 22

Morphine
Oxygen
Nitrate
Aspirin
Ticagrelor
Primary PCI if <90 minutes
Thrombolysis f >90 minutes