Arrhythmias

Question 1

What is the role of the SA node

Answer 1

Generates a normal heart rhythm.

Question 2

How does the SA node fire

Answer 2

Spontaneous

Question 3

What is the ocation of the SA node

Answer 3

The interface between the superior vena cava and the right atrium

Question 4

What is the nature of the cells in the SA node

Answer 4

Specialised conducting tissue.

Question 5

What is the AV node

Answer 5

The electrical connection between the atria and the ventricles.

Question 6

What is represented by the QRS complex

Answer 6

Depolarisation and contraction of the ventricles.

Question 7

what are the indications of the size of the QRS complex

Answer 7

Length of time taken for the ventricles to contract.

Question 8

what are the indications of a long QRS complex

Answer 8

An enlarged heart.

Question 9

What is represented by the gap between the P wave and the QRS complex

Answer 9

Time delay introduced by the AV node activation.

Question 10

What is represented by the T wave

Answer 10

Ventricular diastole - where the ventricles are relaxing/repolarising after one cardiac cycle.

Question 11

What is represented by the PR interval

Answer 11

The start of atrial activation to the start of ventricular activation

Question 12

What is the indication of a long PR interval

Answer 12

An issue with the AV node

Question 13

What is the indication of a short PR interval

Answer 13

An accessory pathway is active which conducts faster than the AV node

Question 14

What is represented by the QT interval

Answer 14

The start of ventricular activation to the start of repolarisation.

Question 15

What is long QT syndrome

Answer 15

A problem with ventricular repolarisation (diastole).

Question 16

What is the impact of long QT syndrome

Answer 16

Lethal rhythms.

Question 17

What are the names of the four heart valves

Answer 17

Tricuspid, mitral, pulmonary and aortic.

Question 18

What is the role of the fibrous rings surrounding the valves

Answer 18

Electrical insulation.

Question 19

What is the role of the AV node

Answer 19

To slowly conduct the impulse from the atria to the ventricles to introduce a time delay so the ventricles contract after the atria.

Question 20

what is the role of the perkinje fibres

Answer 20

To spread the impulse quickly through both ventricles.

Question 21

What are the branches of the bundle of his

Answer 21

Right bundle branch and left bundle branch.

Question 22

What is one second represented by on an ECG graph

Answer 22

5 large squares (25mm)

Question 23

How do you work out heart rate from an ECG trace

Answer 23

Count the number of large squares between successive heart beats and divide 300 by this number.

Question 24

What is a normal PR interval

Answer 24

3 to 5 small squares

Question 25

What is the impact of breathing on heart rate.

Answer 25

When you breath in you draw blood from your vena cavae into the heart and increase pressure in the chest to reduce heart rate.

Question 26

What modulates the heart rate

Answer 26

The parasympathetic nervous system through vagus nerve activation.

Question 27

What is a sinus arrhythmia

Answer 27

The sinus node fires at a variable rate. It speeds up during inspiration and slows down during expiration.

Question 28

What is tachycardia

Answer 28

Heart rate of 100bpm or more,

Question 29

What is bradycardia

Answer 29

Heart rate of 60bpm or less.

Question 30

What is sinus tachycardia

Answer 30

Tachycardia coming from the SA node.

Question 31

What ate the normal causes of sinus tachycardia

Answer 31

Exercise or stress

Question 32

What are the pathological causes of sinus tachycardia

Answer 32

Fever, anaemia, hyperthyroidism, heart failure and others.

Question 33

What is atrial fibrillation

Answer 33

Loss of co-ordination of contraction.

Question 34

What is the main cause of atrial fibrillation

Answer 34

Age

Question 35

What are the complications of atrial fibrillation

Answer 35

Increased risk of clotting and subsequently stroke.

Question 36

What drugs are used in atrial fibrillation to decrease the risk of stroke

Answer 36

Anticoagulants

Question 37

What is sino-atrial disease

Answer 37

Mixture of sinus-tachycardia, bradycardia and atrial "ectopic" beats (atrial fibrillation)

Question 38

What is the treatment for sino-atrial disease

Answer 38

A permanent pacemaker to prevent slow rhythms or antiarrhythmic drugs to prevent rapid rhythms.

Question 39

What are two examples of anti-arrhythmic drugs

Answer 39

Digoxin, amiodarone.

Question 40

what are the normal causes of sinus bradycardia

Answer 40

Sleep, athletic training.

Question 41

What are the pathological causes of sinus bradycardia

Answer 41

Hypothyroidism, hypothermia, sinus node disease, raised inter-cranial pressure.

Question 42

what is a possible cause of a blackout

Answer 42

Rhythm problems - the SA node may stop firing for a short time.

Question 43

What is type 1 AV block

Answer 43

A problem with the AV node causing a long delay (long PR interval) however, the signal still reaches the ventricles.

Question 44

What is second degree AV block

Answer 44

The AV node becomes more fatigued with every heart beat and the signal does not reach the ventricles every time.

Question 45

What is complete AV block

Answer 45

There are no P waves conducting to the ventricles.

Question 46

What is the back-up mechanism for complete AV block

Answer 46

The ventricles can conduct themselves. It is abnormal activation but enough to allow blood to be distributed around the body for a short while.

Question 47

What is the treatment for complete AV block

Answer 47

Permanent pacemaker.

Question 48

What are some possible causes of damage to the AV node

Answer 48

Disease of the aortic valve which is close by, coronary heart disease, damage during heart surgery, sino-atrial disease, drugs (beta-blockers, digoxin, calcium channel blockers).

Question 49

What us used for the treatment of AV nodal block

Answer 49

Removal of any triggers such as drugs, fitting of a permanent pacemaker, atropine or isoprenaline.

Question 50

What is the action of atropine in the treatment of AV nodal block

Answer 50

Blocks the inhibition which vagus nerves give the heart rhythm (through the parasympathetic nervous system)

Question 51

What is the action of isoprenaline in the treatment of AV nodal block

Answer 51

Stimulates the sympathetic nervous system.

Question 52

What is the indication of a saw tooth wave which shows a flutter

Answer 52

A short circuit in the right atrium - atrial fibrillation.

Question 53

What are the causes of atrial fibrillation

Answer 53

Sino-atrial disease, coronary heart disease, valve disease (especially mitral valve), hypertension, cardiomyopathy, hyperthyroidism, pneumonia.

Question 54

What is used in the treatment of atrial fibrillation

Answer 54

A drug to block the AV node and limit heart rate (such as digoxin or a beta-blocker), electrical cardioversion.

Question 55

what are the indications of a fast rhythm with no clear P wave

Answer 55

Ventricular tachycardia

Question 56

what are the indications of a fast rhythm with a clear P wave

Answer 56

Sinus tachycardia

Question 57

What is the impact of ventricular tachycardia

Answer 57

Life threatening - not compatible with consciousness.

Question 58

What is the emergency treatment for ventricular tachycardia

Answer 58

Immediate defibrillation.