Antiarrythmic Drugs Flashcards

1
Q

Name the 5 phases of an action potential

A

Phase 0: Upstroke
Phase 1: Early-fast repolarisation
Phase 2: Plateau
Phase 3: Repolarisation
Phase 4: Diastole

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2
Q

Define excitability

A

Cell can change its internal electrical balance to reach threshold

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3
Q

Define automaticity

A

Cell can generate an electrical impulse without itself being stimulated

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4
Q

Define conductivity

A

Cell can transfer an electrical impulse to the next cell

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5
Q

Name the 6 classes of antiarrythmic drugs

A

Class 1A
Class 1B
Class 1C
Class II
Class III
Class IV

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6
Q

Class I antiarrythmics are ____ blockers

A

Sodium channel

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7
Q

Class II antiarrythmics are ____ blockers

A

Beta

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8
Q

Class III antiarrythmics are ____ blockers

A

Potassium channel

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9
Q

Class IV antiarrythmics are ____ blockers

A

Calcium channel (Non-DHP)

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10
Q

State the duration of actions of class 1A, 1B and 1C antiarrhythmics

A

1A: Intermediate acting
1B: Fast acting
1C: Slow acting

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11
Q

Name a class 1A antiarrhythmic

A

Procainamide

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12
Q

Effect of procainamide on phases

A

Reduces rate of phase 0 rise

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13
Q

Effect of procainamide on conductivity

A

Reduces

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14
Q

Effect of procainamide on automaticity

A

Reduces

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15
Q

Effect of procainamide on ERP

A

Increases

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16
Q

Effect of procainamide on APD

A

Increases

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17
Q

Name a class 1B antiarrhythmic

A

Lidocaine

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18
Q

Effect of lidocaine on phases

A
  1. Reduces rate of phase 0 rise
  2. Shortens phase 3 repolarisation
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19
Q

Effect of lidocaine on conductivity

A

Little effect

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20
Q

Effect of lidocaine on automaticity

A

Reduces

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21
Q

Effect of lidocaine on ERP

A

No change

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22
Q

Effect of lidocaine on APD

A

Reduces

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23
Q

Name a class 1C antiarrhythmic

A

Flecainide

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24
Q

Effect of flecainide on phases

A
  1. Reduces rate of phase 0 rise
  2. Shortens phase 3 repolarisation
25
Q

Effect of flecainide on conductivity

A

Reduces

26
Q

Effect of flecainide on automaticity

A

Reduces

27
Q

Effect of flecainide on ERP

A

No / little effect

28
Q

Effect of flecainide on APD

A

No / little effect

29
Q

State a specific clinical use of a class 1C antiarrhythmic like flecainide

A

Refractory ventricular tachycardias that tend to progress to ventricular fibrillation

30
Q

Name 2 examples of class 2 antiarrhythmics

A

Beta blockers:
1. Metoprolol
2. Propanolol

31
Q

Effect of beta blockers on phases

A

Reduces phase 4 depolarisation

32
Q

Effect of beta blockers on conductivity

A

Prolongs AV conduction

33
Q

Effect of beta blockers on automaticity

A

Reduces

34
Q

Effect of beta blockers on ERP

A

No change

35
Q

Effect of beta blockers on APD

A

No change

36
Q

General sympatholytic effect of beta blockers on the heart

A

Reduce heart rate and contractility of the heart

37
Q

4 specific clinical uses of beta blockers as an antiarrhythmic

A
  1. Atrial fibrillation
  2. AV nodal reentrant tachycardia
  3. Tachycardia caused by sympathetic activation
  4. Reduces sudden arrhythmic death post myocardial infarction
38
Q

Name a class 3 antiarrhythmic

A

Amiodarone

39
Q

Effect of amiodarone on phases

A

Prolongs phase 3 repolarisation without effect on phase 0

40
Q

Effect of amiodarone on ERP

A

Increase

41
Q

Effect of amiodarone on APD

A

Increase

42
Q

Besides blocking potassium channels, state 3 other MOA of amiodarone

A
  1. Block sodium channels
  2. Blocks adrenergic receptors
  3. Block calcium channels
43
Q

Amiodarone is metabolised in the ___ to the active metabolite ___

A

Liver,
Desethylamiodarone

44
Q

State 2 clinical uses of amiodarone

A
  1. Effective in maintaining normal sinus rhythm in patients with atrial fibrillation
  2. Effective in prevention of reentrant ventricular tachycardia
45
Q

State 2 ADRs of amiodarone use

A
  1. Symptomatic bradycardia
  2. Heart block
46
Q

State 2 examples of a class IV antiarrhythmic

A

Non-DHP Calcium channel blockers:
1. Verapamil
2. Diltiazem

47
Q

Effects of non-DHP CCBs on phases

A

Prolongs phase 4 depolarisation

48
Q

Effect of non-DHP CCB on AV node conduction

A

Reduces conductivity on AV node

49
Q

Effect of non-DHP CCB on ERP

A

Increase

50
Q

Effect of non-DHP CCB on APD

A

Increase

51
Q

State 3 clinical uses of verapamil

A
  1. Supraventricular tachycardia
  2. Hypertension (use DHP CCB as a first line instead)
  3. Angina
52
Q

Verapamil is contraindicated in patients with ___

A

Preexisting depressed cardiac function

53
Q

State an adverse effect of verapamil use

A

Hypotension

54
Q

State 2 effects on calcium and potassium that adenosine has in the heart

A
  1. Stimulates cardiac K+ channels
  2. Inhibits calcium current
55
Q

State 2 cardiac effects of adenosine

A
  1. Suppression of atrioventricular nodal conduction
  2. Increase AV nodal refractory period
56
Q

Half life of adenosine in blood

A

Less than 10 seconds

57
Q

State a clinical use of adenosine

A

Supraventricular tachycardia

58
Q

State 5 adverse effects of adenosine use

A
  1. Flushing
  2. Shortness of breath / Chest burning
  3. Induction of AV block or AF
  4. Headaches
  5. Hypotension