Arrhythmias

Question 1

What are the two classes of arrhythmias described by where the arrhythmia arises?

Answer 1

Supraventricular

Ventricular

Question 2

Supraventricular arrhythmias tend to have narrow QRS complexes. True/False?

Answer 2

True

Because the arrhythmia does not originate from ventricles

Question 3

The AV node is the only point of electrical contact between the atria and ventricles. What may additionally be present to cause pathological conduction?

Answer 3

Fibrous ring

Question 4

What are ectopic beats?

Answer 4

Beats/rhythms that originate outwith the SA node

Question 5

Ectopic beats may not be dangerous. True/False?

Answer 5

True

Question 6

Why might ectopic beats not be harmful?

Answer 6

Depends on where they originate - if in non-contractile areas, they are unlikely to affect cardiac output

Question 7

Name the main supraventricular arrhythmias

Answer 7

SVTs: atrial fibrillation, atrial flutter, ectopic atrial tachycardia
Bradycardias: sinus bradycardia, sinus pauses

Question 8

Name the main AV node arrhythmias

Answer 8

AV node reentry
Accessory pathway
AV block (1st, 2nd, 3rd degree)

Question 9

Name the main ventricular arrhythmias

Answer 9

Premature ventricular complex
Ventricular tachycardia
Ventricular fibrillation
Asystole

Question 10

What are the 3 main physiological types of arrhythmia?

Answer 10

Altered automaticity
Triggered activity
Reentry (accessory pathway)

Question 11

List the investigations you would do for arrythmias

Answer 11

ECG/exercise ECG/24hr ECG
CXR
Echocardiogram
Event recorder
EP study (induce arrhythmia to map pathway)

Question 12

How would acute SVT be managed?

Answer 12

Vagal manoeuvres, carotid massage
IV adenosine
IV verapamil

Question 13

Give examples of some vagal manoeuvres

Answer 13

Holding your breath and bearing down (Valsalva)
Immersing face in ice-cold water (diving reflex)
Holding nose/unblocking ears

Question 14

What is the treatment of choice for managing chronic arrhythmias?

Answer 14

Radiofrequency ablation

Question 15

What is radiofrequency ablation?

Answer 15

Selective cauterisation of cardiac tissue to prevent tachycardia
Target reentry circuit or automatic myocite

Question 16

Which drugs must be stopped before radiofrequency ablation?

Answer 16

Antiarrhythmic drugs 3-5 days beforehand

Question 17

What is notorious for causing AV block in young people?

Answer 17

Cytomegalovirus

Question 18

Describe 1st degree AV block

Answer 18

PR interval increased (greater than 0.2s)

Question 19

Describe 2nd degree Mobitz 1 AV block

Answer 19

PR interval gets progressively longer, followed by dropped QRS

Question 20

Describe 2nd degree Mobitz 2 AV block

Answer 20

Lonely P waves not followed by QRS

N.B. PR interval not prolonged

Question 21

Describe 3rd degree AV block

Answer 21

P waves without QRS complexes

i.e. no association between atrial and ventricular systole

Question 22

What is typical of an ECG showing ventricular tachycardia?

Answer 22

Broad QRS complexes

Question 23

What is the difference between monomorphic and polymorphic VT?

Answer 23

In monomorphic VT, the QRS complexes look similar

Question 24

How would acute VT be treated?

Answer 24

DC cardioversion if unstable

Adenosine if unsure it’s VT

Question 25

What are the 3 classifications of AF?

Answer 25

Paroxysmal Persistent Permanent

Question 26

Define paroxysmal AF

Answer 26

Recurrent AF, lasting less than 48 hours

Question 27

Define persistent AF

Answer 27

AF lasting greater than 48 hours which can be cardioverted to normal sinus rhythm

Question 28

Define permanent AF

Answer 28

AF that is unable to be restored to normal sinus rhythm via pharma + non pharmacological methods

Question 29

What is meant by lone AF?

Answer 29

AF where a cause cannot be found

Question 30

What would a typical ECG of AF show?

Answer 30

Rate greater than 300bpm Irregularly irregular P waves absent

Question 31

What are the two management pathways for AF patients?

Answer 31

``` Rhythm control (get back to NSR) Rate control (accept AF, control ventricular rate) ```

Question 32

What pharmacological therapy can be used for rate control in AF?

Answer 32

Digoxin B blockers Verapamil, diltiazem

Question 33

How can NSR be restored in AF (rhythm control)?

Answer 33

Amiodarone | DC cardioversion

Question 34

Class I anti-arrhythmic drugs act on which phase of the AP and block which channels?

Answer 34

Act on phase 0 | Block Na+ channels

Question 35

Name a class I anti-arrhythmic drug

Answer 35

Flecainide | Lignocaine

Question 36

Class II anti-arrhythmic drugs act on which phase of the AP and block which channels?

Answer 36

Act on phase 4 | Block B receptors (B blockers)

Question 37

Class III anti-arrhythmic drugs act on which phase of the AP and block which channels?

Answer 37

Phase 3 | Block K channels

Question 38

Name a class III anti-arrhythmic drug

Answer 38

Amiodarone | Sotalol

Question 39

Class IV anti-arrhythmic drugs act on which phase of the AP and block which channels?

Answer 39

Phase 2 | Block Ca channels

Question 40

What would a typical ECG of atrial flutter look like?

Answer 40

Saw tooth baseline | Regular rhythm