ECG and rhythm disorders

Question 1

What are the kinds of abnormalities ECG can tell us about? (3)

Answer 1

• Conduction abnormalities
• Structural (e.g. ventricular hypertrophy)
• Perfusion (whether the muscle is ischaemic or infarct e.g. MI)

Question 2

What does the steepness of the line denote to in an ecg?

Answer 2

The velocity of the action potential.

Question 3

What does a downwards deflection mean in an ecg

Answer 3

Current is traveling towards the negative electrode.

Question 4

What does an upwards deflection mean in an ecg

Answer 4

Current is travelling towards the positive electrode.

Question 5

What does an isoelectric line represent in an ecg. (Flat line)

Answer 5

No net change in voltage, vectors are perpendicular to the lead.

Question 6

Using the rule of Ls describe how Lead I, II & III is placed.

Answer 6

Question 7

Explain how the electrodes are placed on the chest from V1 to V6

Answer 7

Question 8

What is the R-R interval of this ECG, (each square is 0.04s)

Answer 8

0.6s-1.2s

Question 9

What is the P-wave duration of this ECG, (each square is 0.04s)

Answer 9

80ms/0.08s

Question 10

What is the P-R interval of this ECG, (each square is 0.04s/40ms)

Answer 10

120-200ms (80ms)

Question 11

What is the qrs duration of this ECG,

Answer 11

<120ms

Question 12

When calculating the cardiac axis, which two leads are used?

Answer 12

Lead I, Lead aVF

Question 13

Calculate the cardiac axis, (using calculator and trig) if Lead II has a +4.5 net deflection and Lead aVL has a +2 net deflection.

Answer 13

36 degrees

Question 14

What is the ECG reporting procedure?

Answer 14

1) Is it the correct recording?

2) Review the signal quality and leads

3) Verify the voltage and paper speed

4) Review the patient background if available e.g. if the ECG has AF then reviewing notes will show if they know or not so you know whether or not to tell them

Question 15

What does this ECG show? And what can cause this.

Answer 15

Sinus bradychardia
-Can be healthy, caused by medication or vagal stimulation

Question 16

What does this ECG show?

Answer 16

Sinus tachycardia

Question 17

What does this ECG show

Answer 17

Sinus arrythmia

Question 18

What does this ECG show?

Answer 18

Atrial fibrilation

Question 19

What does this ECG show?

Answer 19

Atrial flutter

Question 20

What does this ECG show?

Answer 20

First degree heart block.

Question 21

What does this ECG show?

Answer 21

Second degree heart block (Mobitz I/Wenckebach)

Question 22

What does this ECG show?

Answer 22

Second degree heart block (Mobitz II)

Question 23

What is the main difference between secondary heart blocks Mobitz I and Mobitz II

Answer 23

Mobitz I has gradual prolongation of the PR interval, Mobitz II does not and can rapidly deteriorate into third degree heart block.

Question 24

What does this ECG show?

Answer 24

Third degree (complete) heart block.

Question 25

What needs to be in place with a third degree (complete) heart block.

Answer 25

A backup pacemaker.

Question 26

What does this ECG show?

Answer 26

Ventricular tachycardia

Question 27

What does this ECG show?

Answer 27

Ventricular fibrillation

Question 28

What does this ECG show?

Answer 28

ST elevation

Question 29

What does this ECG show?

Answer 29

ST depression

Question 30

What two types of irregular ECG/ heart rhythms are shockable with a defibrillator?

Answer 30

-Ventricular tachycardia
-Ventricular fibrillation

Question 31

What does the turbulent flow in atrial fibrillation increase the risk of?

Answer 31

Blood clot

Question 32

If Leads 1 and aVF are both positive what is the axis deviation?

Answer 32

Normal axis

Question 33

If lead 1 is POSITIVE and lead aVF is NEGATIVE what is the axis deviation?

Answer 33

Possible LAD

Question 34

If Lead 1 is negative and lead aVF is positive what is the axis deviation?

Answer 34

RAD

Question 35

If lead 1 is negative and aVF is also negative what is the axis deviation?

Answer 35

EXTREME axis deviation