ECG and Safety Biomarkers

Question 1

What are the normal values for an adult resting heart rate?

Answer 1

60-100 bpm.

Question 2

What is the normal value for the PR interval on an ECG?

Answer 2

0.12-0.2 seconds.

Question 3

What is a normal value for the QRS complex on an ECG?

Answer 3

<0.12 seconds.

Question 4

What is the normal QT interval for female patients on an ECG?

Answer 4

< half of RR
< 0.44 seconds

Question 5

What is the normal QT interval for male patients on an ECG?

Answer 5

< half of RR
< 0.40 seconds

Question 6

What does the large box represent on a standard ECG output?

Answer 6

Width = 0.2 seconds
Height = 0.5 mV amplitude

Question 7

What does the small box represent on a standard ECG output?

Answer 7

Width = 0.04 seconds
Height = 0.1 mV amplitude

Question 8

How do you calculate HR from an ECG?

Answer 8

Multiply the number of R waves in 10 seconds by 6 to get the number of beats per minute.

Question 9

What are the vital signs monitored during a clinical trial?

Answer 9

1. Heart rate (HR)
2. Blood pressure (BP)
3. Respiratory rate (RR)
4. Body temperature
5. Pulse oximetry

Question 10

What is the normal blood pressure for an adult and when may this differ?

Answer 10

120/80 mmHg. This will increase in older patients as their blood vessels lose elasticity, leading to increased pressure in the vessels.

Question 11

What does systolic pressure represent?

Answer 11

The maximum pressure recorded during contraction of the ventricles.

Question 12

What does diastolic pressure represent?

Answer 12

The minimum pressure recorded during relaxation (prior to the next contraction of the ventricles).

Question 13

What is a typical resting heart rate and when does this differ?

Answer 13

60-100 bpm. Young adults tend to have higher resting heart rates due to them having stronger adrenergic activity - this can also be visualised as a stronger wave on ECG. Neonates also have a much higher resting heart rate.

Question 14

What is tachycardia?

Answer 14

A fast heart rate, typically > 100 bpm.

Question 15

What is bradycardia?

Answer 15

A slow heart rate, typically <60 bpm.

Question 16

What is a typical adult resting respiratory rate?

Answer 16

12-20 breaths per minute. This value can vary with age.

Question 17

What is pulse oximetry?

Answer 17

A measure of oxygen saturation in the blood which acts as a proxy for the amount of oxygen in the blood.

Question 18

What are normal values for pulse oximetry and when does this differ?

Answer 18

Healthy adults should have a value of 95-100. Adults with COPD may have a lower value due to blood being inadequately oxygenated due to the lung disease.

Question 19

What value on pulse oximetry is a cause for concern in healthy adults?

Answer 19

Below 95.

Question 20

What are common laboratory tests performed in clinical trials?

Answer 20

1. Haematology
2. Blood glucose
3. Electrolytes
4. Liver function test
5. Lipids
6. Creatine kinase
7. Others including thyroid, amylase, troponin

Question 21

What is urinalysis used for?

Answer 21

To look at the composition of the urine and monitor for nephrotoxicity. Key things to check are blood, protein, glucose and infection.

Question 22

What does P represent on an ECG?

Answer 22

Depolarisation and contraction of the atria.

Question 23

What does the PR interval on an ECG represent?

Answer 23

The time taken from initiation of contraction of the atria to the end of the contraction
A delay may mean that blood is leaving the heart too slowly.

Question 24

What does the QRS interval on an ECG represent?

Answer 24

The time taken for the depolarisation and contraction of the ventricles. The amplitude of R gives the strength of the contraction.

Question 25

What does the T wave on an ECG represent?

Answer 25

The repolarisation and relaxation of the ventricles.

Question 26

What does the QT interval on an ECG represent?

Answer 26

The time period from the beginning of ventricular contraction to the time when it can begin again.

Question 27

What does the ST segment on an ECG represent?

Answer 27

The period in which the ventricles are not receptive to another electrical signal as they have not yet repolarised. Extra systole occurs when there is an extra beat during this segment.

Question 28

What is pharmacovigilance?

Answer 28

Monitoring the safety aspects of a clinical trial to determine whether or not adverse events are deemed acceptable.

Question 29

Who is responsible for pharmacovigilance?

Answer 29

It is the ultimate responsibility of the Sponsor, but it can be delegated to a person, institution or research organisation.

Question 30

What is electrocardiography (ECG)?

Answer 30

ECGs are a recording of the electrical activity of the heart. They are useful for detecting conduction abnormalities.

Question 31

What are the 2 natural pacemakers in the heart?

Answer 31

1. Sinoatrial node - input for contraction of the atria. 2. Atrioventricular node - input for the contraction of the ventricles.

Question 32

What is the pattern of electrical activity in the heart?

Answer 32

Depolarisation is initiated in the SA node. There is slow conduction through the AV node then rapid conduction through Purkinje fibres.

Question 33

How many leads does a typical ECG have?

Answer 33

12 - 6 leads applied to the chest (in the direction of electrical activity) and 4 leads applied to the limbs.

Question 35

How can you determine what region of the heart the abnormality is in?

Answer 35

Each ECG derivative is representative of a different view of the heart - if a beat is abnormal in one derivative but not in the others, that is the region where the issue is.

Question 36

What is seen on an ECG in atrial fibrillation?

Answer 36

1. An atrial rate of 400-650 bpm. 2. A lack of P wave (QRS is normal). 3. A wandering baseline. 4. Irregularly irregular rhythm.

Question 37

What is seen on an ECG in a myocardial infarction or ischaemia?

Answer 37

1. Abnormalities in the ST segment or T wave. 2. ST elevation - the ST segment will not fall on the iso-electric line.

Question 38

What is a prolonged QT interval and what is it associated with?

Answer 38

A QT interval > 0.44 sec in males and > 0.46 sec in females is a marker of myocardial electrical instability. This is associated with ventricular arrhythmia, syncope and sudden death. At > 0.5 sec, there is a risk of Torsade des Pointes which can escalate to VF and death.