Basic ECG's

Question 1

What does an ECG represent?

Answer 1

The electrical activity leading to heart contraction which results in blood being pumped around the body

Question 2

What function do all heart cells possess?

Answer 2

Automaticity

- All cells can start an electrical signal if normal mechanisms fail

Question 3

What is the ‘normal pacemaker’ called?

Answer 3

Sino Atrial Node (SA node)

Question 4

Where should all electrical activity start?

Answer 4

SA node

Question 5

List the electrical and mechanical pathway of heart contraction

Answer 5

1. SA node
2. Atrial contraction (signal passes over atria)
3. AV node picks up and holds signal (allows ventricular filling)
4. Signal passes via bundle branches and purkinje fibres
5. Stimulates ventricular contraction

Question 6

What does the isoelectric line represent?

Answer 6

‘Flat line’ where all electrical activity should start and finish

Question 7

What is the P wave and what does it represent?

Answer 7

• A small rounded +ve wave at the start of an ECG
• Represents electrical signal moving over atria
• Results in atrial contraction

Question 8

What does the PR interval show?

Answer 8

A pause in activity as the signal is held at the AV node

Question 9

What is the QRS complex and what does it represent?

Answer 9

• Tallest waveform (ventricles largest area in heart)
• Signal moving through ventricles
• Ventricular contraction

Question 10

What is the ST segment?

Answer 10

Flat line between QRS and T wave

Question 11

What can the ST segment show?

Answer 11

An acute myocardial infarction

STEMI

Question 12

What is the T wave and what does it show?

Answer 12

• Larger rounded wave
• Electrical activity returning to normal for next contraction
• Ventricular REPOLARISATION

Question 13

Do all MI’s present with ST elevation?

Answer 13

No
nSTEMI
Look at other signs and symptoms
ECG not definitive diagnosis

Question 14

What does the QT interval show?

Answer 14

Time taken for ventricular contraction AND relaxation to occur

Question 15

What 6 elements represent a ‘normal’ ECG?

Answer 15

1. Begins with P wave
2. PR interval of defined length
3. QRS tall, thin and spikey
4. Flat ST segment
5. Rounded T wave
6. QT interval of appropriate length

Question 16

What is the most important thing to keep in mind when identifying abnormal ECG’s?

Answer 16

Know what normal looks like

bear in mind not everyone’s normal is textbook normal

Question 17

What 4 main issues lead to abnormal ECG’s?

Answer 17

1. Coronary circulation issues
2. Infection
3. Nervous control issues
4. Electrical signals not functioning correctly

Question 18

What conditions are caused by issues with coronary circulation?

Answer 18

• Angina (narrow arteries)

- MI (blocked coronary arteries)

Question 19

What is an infection of the heart called?

Answer 19

Pericarditis

Question 20

What can cause nervous control issues of the heart?

Answer 20

HEAD INJURY
Damage to higher brain functions which control rate and rhythm
Change in Inter Cranial Pressure (ICP) –> Bradycardia

Question 21

What can ECG ‘leads’ tell you?

Answer 21

Which part of the heart is impacted

Question 22

What can ST elevation show?

Answer 22

MI

Question 23

What is important to bear in mind when diagnosing ST elevation?

Answer 23

It must be seen in at least 2 related ‘leads’ corresponding to the same area of the heart

Question 24

What does ST depression show?

Answer 24

Ischaemia

Question 25

What condition can ST depression alone indicate?

Answer 25

Angina

Question 26

What can reciprocal ST changes (elevation and depression) indicate (mirror image)?

Answer 26

MI

Question 27

What 6 signs are important to bear in mind when diagnosing cardiac problems ALONGSIDE an ECG?

Answer 27

1. Chest pain 2. Blood Pressure 3. Pulse 4. Respiratory Rate 5. Capillary Refill 6. Glasgow Coma Scale

Question 28

Name some symptoms associated with cardiac problems

Answer 28

``` Sweating Dizziness Fainting Vomiting Nausea Anxiety Pallor History Onset/Severity Breathless Pain on exertion? Social history Family history ```

Question 29

What are the 2 types of cardiac rhythms is cardiac arrest?

Answer 29

- Shockable :) | - Non-Shockable :(

Question 30

Name the 2 'Shockable' cardiac rhythms

Answer 30

- Ventricular Fibrillation (VF) | - PULSELESS Ventricular Tachycardia (pVT)

Question 31

Name the 2 'Non-Shockable' cardiac rhythms

Answer 31

- Asystole | - Pulseless Electrical Activity (PEA)

Question 32

What are the characteristics of VF?

Answer 32

- No organised activity - No proper 'pumping' of the heart - No pulse - Random presentation

Question 33

What are the characteristics of pVT?

Answer 33

- Each wave looks the same - Can indicate organised activity (rate too fast for heart to pump) - No pulse

Question 34

What are the characteristics of Asystole?

Answer 34

- No electrical activity = No cardiac output | - SA node has not corrected itself

Question 35

What are the characteristics of PEA?

Answer 35

- No pulse - Activity NOT VT and pVT - Ventricles failing - Complexes wide, odd and irregular

Question 36

What does an ECG 'lead' show you?

Answer 36

A view of the heart