ECG

Question 1

What does ECG stand for?

Answer 1

Electrocardiograph or electrocardiogram

Question 2

What is an ECG?

Answer 2

Recording of the electrical activity of the heart

Question 3

What are the placements for 3 lead ECG?

Answer 3

RA - Right Arm

LA - Left Arm

RL - Right Leg

LL - Left Leg

Question 4

What is Eithonven’s Triangle? (4)

Answer 4

It is an imaginary formation of three lung leads in a triangle using an ECG, formed by the two shoulders and the pubis.
The shape forms an equal lateral triangle with the heart at the centre.

The top part of the triangle is lead 1 from the right arm to the left arm.

The right hand region is lead 2 from the right arm to the left leg.

The left hand region is lead 3 from the left arm to the left leg.

Question 5

When is an ECG used?

Answer 5

Investigate symptoms of possible heart problems, such as chest pain, palpitations (suddenly noticeable heartbeats), dizziness and shortness of breath.

Prior to surgery or drug treatment

In the assessment of collapsed patient or in cardiac arrest

Question 6

What can ECGs help detect?

Answer 6

Arrhythmia - bradycardia, tachycardia, atrial fibrillation, ectopic?

Coronary heart disease - heart blood supply is blocks or interrupted by build up of fatty substances

Heart attacks - where supply of blood to heart is suddenly blocked

Cardiomyopathy - heart walls become thickened or enlarged

Question 7

What is a three lead ECG commonly used for?

Answer 7

Commonly used for gross rhythm abnormality assessment in cardiac arrest and for continuous monitoring

Question 8

When is a 12 lead ECG used?

Answer 8

Most commonly used for diagnostics in acute coronary syndromes and cardiac assessment.

Question 9

What are some positives of ECGs?

Answer 9

Represents data in graphical form (visible)

Informative and provides information such as chest pain, shortness of breath, abnormal pain etc

Can detect silent cardiac condition which could be result of surgery or anaesthesia

Safe method

Non-invasive

Inexpensive

Easy to perform

Equipment widely available

Question 10

What are some disadvantages of ECGs?

Answer 10

Provides graph which may not reflect severe underlying heart issues

Wires and probes for testing. May be uncomfortable and restricts body movements

No all heart problems would be detected, eg. A vulnerable plaque which is a form of atheroma. Because artery walls enlarge in response to enlarging plaques they do not affect blood flow and may not be detected on ECG but is major cause of heart attacks

Question 11

What are the main components of ECGs?

Answer 11

P 
Q
R
S
T

Question 12

What is the P wave?

Answer 12

A small deflection representing the depolarising of the atria

Question 13

How many squares does a p wave normally take?

Answer 13

2-3 small squares

Question 14

What is the PR interval?

Answer 14

Beginning of P wave to the beginning of the QRS complex

Question 15

How many boxes is taken at the PR interval?

Answer 15

3-5 boxes

Question 16

What is the QRS complex?

Answer 16

Represents ventricular depolarisation

Q wave is the first negative deflection and is not always present

Question 17

How many boxes is taken at the QRS complex?

Answer 17

1-3 boxes

Question 18

What is a T wave?

Answer 18

A small rounded deflection (asymmetric) and is due to depolarisation is the ventricles

Question 19

What is lost in the QRS complex and nit visible?

Answer 19

Atrial repolarisation

Question 20

Is depolarisation positive or negative?

Answer 20

+40mV

Question 21

Is repolarisation negative or positive?

Answer 21

Negative

Question 22

Why is a T wave positive?

Answer 22

The septum and deep endocardium areas do depolarise first but they have a longer period of contraction

Therefore most of the outer surface of the ventricles, especially near the apex are the first to repolarise

Question 23

What happens to QT intervals as the heart rate increases?

Answer 23

Shortens

Question 24

What happens to QT intervals when Drugs is taken or the patient has a disease?

Answer 24

Shortens

Question 25

What is important about the ST segment that should be taken into consideration ?

Answer 25

Should come back to the iso-electric line

Question 26

What do U waves represent?

Answer 26

A wave of late repolarisation

Question 27

How do you calculate heart rate?

Answer 27

Divide 390 by the number of large squares (0.2 sec) between R-R intervals.
THIS ONLY APPLIES TO REGULAR RHYTHMS

Use the 10 second rule

Question 28

Illustrate the 10 point plan:

Answer 28

What is the heart rate?
Is it regular?
Are the P waves present?
Are the P waves all the same size and shape?
Is there a P wave before every QRS complex?
Is there a QRS complex after every P wave?
Is the PR interval normal?
Is the QRS interval normal?
Are the T waves normal?
Is the ST segment iso-electric?

Question 29

How would you prepare a patient for ECG?

Answer 29

Expose as necessary

Select and prepare electrode site. Wipe if necessary

Small patches may need to be shaved if patient is hairy

Attach leads to electrodes

Apply electrodes to patient

Question 30

What are some artefacts that can effect ECG readings?

Answer 30

Sweaty, moist skin

Oily, dirty or scaly skin

Excessive chest hair

Dry gel in electrodes

Patient movement or lead movement

Muscle tremor

Electrical interference

Low battery

Mobile phones

Question 31

What is a characteristic of ST elevation?

Answer 31

Above iso-electric line

Question 32

What is characteristic of ST depression?

Answer 32

Below iso-electric line

Question 33

How would you apply a 12 lead ECG? (6)

Answer 33

V1 = 4th intercostal space right sternal border

V2 = 4th intercostal space left sternal border

V3 = between V2 and V4

V4 = 5th intercostal space between mid-clavicle left side

V5 = horizontally from V4 left anterior axilla

V6 = horizontally from V5 left mid axilla