Arrythmias

Question 1

Define arrhythmia.

Answer 1

A disturbance in the normal rhythmic beating of the heart.

Question 2

Give 2 symptoms of arrhythmias.

Answer 2

Palpitations, breathlessness, dizziness.

Question 3

What is the absolute refractory period?

Answer 3

Is the period of time during which a second action potential ABSOLUTELY cannot be initiated

Question 4

What is the relative refractory period?

Answer 4

Is the interval immediately following the Absolute Refractory Period during which initiation of a second action potential is INHIBITED, but not impossible.

Question 5

Give 3 ways to classify an arrhythmia.

Answer 5

By rate, by location, by cause.

Question 6

Which two ways can arrhythmias be distinguished by rate?

Answer 6

Inappropriate bradyarrhythmia (<60bpm), inappropriate tachyarrhythmia (>100bpm).

Question 7

Which two ways can arrhythmias be distinguished by location?

Answer 7

Atrial (supraventricular), ventricular.

Question 8

Which two ways can arrhythmias be distinguished by cause?

Answer 8

Disorders of impulse generation, disorders of impulse conduction.

Question 9

Give 3 types of arrhythmias.

Answer 9

Atrial fibrillation, complete heart block, ventricular tachycardia, ventricular fibrillation, long QT syndrome, bradyarrhythmia (bradycardia), tachyarrhythmia (tachycardia), atria flutter.

Question 10

Define atria fibrillation.

Answer 10

Common abnormal heart rhythm due to disorganised waves from different places in the atria

Question 11

Give 2 things you would see on an atrial fibrillation ECG.

Answer 11

Lack of p waves. Small fibrillatory (‘f’) waves of varying amplitude. High frequency QRS complexes causing tachycardia.

Question 12

How many classes of anti-arrhythmic drugs are there?

Answer 12

4

Question 13

Classes 1 and 3 do what to tackle AF?

Answer 13

Target source of arrhythmia to suppress re-entry.

Question 14

Give an example of a class 3 drug.

Answer 14

Amiodarone.

Question 15

Give an example of a class 2 drug.

Answer 15

Bisoprolol (Beta receptor blocker inhibits AVN conduction).

Question 16

Give an example of a class 1 drug.

Answer 16

Flecainide (Na ion channel blocker suppresses conduction).

Question 17

What does adenosine do?

Answer 17

Slows AV nodal conduction.

Question 18

What does digoxin do?

Answer 18

Stimulates vagus and slows AV nodal conduction.

Question 19

Give an example of a class 4 drug.

Answer 19

Verapamil (Ca ion channel blocker inhibits AVN conduction)

Question 20

Classes 2 and 4 do what to tackle AF?

Answer 20

Reduce the ability of impulses conducted through AV (rate control).

Question 21

What does re-entry mean?

Answer 21

Re-excitation of the heart after the refractory period has ended, as the propagating impulse has failed to die out.

Question 22

All parts of the conduction system are latent pacemakers, what does that mean?

Answer 22

They can cause premature, ectopic heart beat outside the normally functioning SA node of the heart.

Question 23

Bradycardia can have two causes. List them.

Answer 23

SAN slows down. Impulse from SAN blocked.

Question 24

Tachycardia can have two causes. List them.

Answer 24

Disorders of impulse generation. Disorders of impulse conduction (re-entry).

Question 25

What is a complete (3rd degree) heart block?

Answer 25

Blocked connection between the atria and ventricles.

Question 26

What is the effect of a complete (3rd degree) heart block

Answer 26

Bradyarrhythmia.

Question 27

What is the cause of a complete (3rd degree) heart block

Answer 27

Atherosclerotic coronary heart disease.

Question 28

What would you see on an ECG for a complete (3rd degree) heart block?

Answer 28

QRS complex dissociates from the p wave as the atria and ventricles beat independently.

Question 29

What is the treatment for a complete (3rd degree) heart block?

Answer 29

Implantation of a permanent pacemaker to generate cardiac rhythm.

Question 30

Name 2 things tachyarrhythmias can be caused by.

Answer 30

Ischaemia, myocardial scarring, congenital conditions.

Question 31

Define ventricular tachycardia.

Answer 31

Rapid ventricular beats caused by an ectopic site in one of the ventricles.

Question 32

What is radiocatheter ablation?

Answer 32

It is a procedure that uses radiofrequency energy to destroy a small area of heart tissue that is causing rapid and irregular heartbeats.

Question 33

Symptoms of ventricular tachycardia.

Answer 33

Chest pain, shortness of breath.

Question 34

What is the hallmark of ventricular tachycardia on an ECG.

Answer 34

Don't see p waves, as they are insignificant (ventricles contracting too fast). AV dissociation (independent atrial contraction to ventricles).

Question 35

What do class 1 drugs do?

Answer 35

Suppress conduction completely.

Question 36

What do class 2 drugs do?

Answer 36

Reduce excitability to inhibit AVN conduction.

Question 37

What do class 3 drugs do?

Answer 37

Prolong the refractory period to slow conduction.

Question 38

What do class 4 drugs do?

Answer 38

Inhibit AVN conduction.

Question 39

What do implantable defibrillators do?

Answer 39

They sense and differentiate arrhythmias to return the cardiac system to sinus rhythm.

Question 40

Give 2 ways ventricular tachycardia is treated?

Answer 40

Class 1/3 drugs to suppress conduction/slow conduction. Class 2 drugs can reduce excitability. Implantable defibrillators.

Question 41

Define ventricular fibrillation.

Answer 41

Disorganised activity of the heart due to disorganized electrical activity in the ventricles.

Question 42

Give a cause one cause of ventricular fibrillation.

Answer 42

Ischaemic heart disease. Cardiomyopathy.

Question 43

Give a symptoms of ventricular fibrillation.

Answer 43

Unconsciousness. Death.

Question 44

What is the hallmark of ventricular fibrillation?

Answer 44

Disorganised electrical activity, which fades as heart dies.

Question 45

What is used to treat ventricular fibrillation?

Answer 45

Defibrillation - stops the heart and allows SAN to restart.

Question 46

Define long QT syndrome.

Answer 46

It's a condition which affects repolarization of the heart after a heartbeat.

Question 47

What is the hallmark ECG for a patient with Long QT syndrome?

Answer 47

A long distance between Q and the next T wave.

Question 48

Give 2 causes of ventricular tachycardia.

Answer 48

Cardiac scarring. Congenital e.g. Brugada syndrome. Re-entry.