Cardiac Arrhythmias Flashcards

1
Q

What are the different classes of anti-arrhythmic drugs?

A

Class I - block Na+ channels
Class II - β-blockers
Class III - block K+ channels
Class IV - calcium channel blockers

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2
Q

What are the action of drugs used for abnormal action potential generation?

A

Decrease phase 4 slope in pacemaker cells

Raises threshold for action potential

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3
Q

What are the actions of drugs used for abnormal conduction of action potential?

A

Decrease conduction velocity

Increased effective refractory period so cell can’t be depolarised again

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4
Q

What causes arrhythmias to occur?

A

Automatic or triggered activity
Re-entry due to a scar, anatomy of AV node
WPW

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5
Q

What are examples of class IA anti-arrhythmics?

A

Quinidine

Procainamide

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6
Q

What are the effects of class IA ant-arrhythmics on cardiac activity?

A

Decreased conduction
Increased refractory period
Decreased automaticity
Increase threshold for action potential

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7
Q

What are the uses of class IA anti-arrhythmics?

A

Quinidine; maintains sinus rhythm in AF and atrial flutter, and prevents recurrence

Procainamide; acute IV treatment of SVT and ventricular arrhythmias

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8
Q

What are examples of class IB anti-arrhythmics?

A

Lidocaine

Mexiletine

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9
Q

What are the effects of class IB anti-arrhythmics on cardiac activity?

A

Slightly decreased ADP
Increase threshold for action potential
Decrease phase 0 conduction in fast beating or ischaemic tissue

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10
Q

What are some side effects of class IA anti-arrhythmics?

A
Hypotension - reduced CO 
Proarrhythmic - increased QT interval 
Dizziness, confusion, insomnia, seizure 
GI Sx 
Lupus-like syndrome
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11
Q

What is a use of class IB anti-arrhythmics?

A

Acute ventricular tachycardia

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12
Q

What are some side effects of class IB anti-arrhythmics?

A

CNS effects - dizziness, drowsiness

Abdo upset

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13
Q

What are some examples of class IC anti-arrhythmics?

A

Flecainide

Propafenone

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14
Q

What are the effects of class IC anti-arrhythmics on cardiac activity?

A

Decreased phase 0
Decreased automaticity
Increased APD

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15
Q

What are the used of class IC anti-arrhythmics?

A

Supraventricular arrhythmias - fibrillation and flutter
Premature ventricular contractions - ventricular ectopics
Wolff-Parkinson-White syndrome

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16
Q

What are some side effects of class IC anti-arrhythmics?

A

Pro-arrhythmic and sudden death - esp w/ chronic use and structural heart disease
Increase ventricular response to supraventricular arrhythmias - need to body IC AVN
CNS and GI effects

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17
Q

What are some class II anti-arrhythmics?

A

Propranolol
Bisoprolol
Metoprolol
Esmolol

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18
Q

What is the MOA of class II anti-arrhythmic drugs?

A

β-blockers

Increase refractory period in AV node to slow AV conduction
Decreases phase 4 depolarisation

19
Q

What is the MOA of class III anti-arrhythmic drugs?

A

Prolongs depolarisation

Increases refractory period

20
Q

What is the MOA of class IV anti-arrhythmic drugs?

A

Calcium channel blockers
Slows conduction through AV node
Increases refractory period in the AV node

21
Q

What are class II anti-arrhythmic drugs used for?

A

Treat sinus and catecholamine dependent tachycardia
Wolff-Parkinson-White syndrome
Slows AV conduction to protect ventricles from high atrial rates

22
Q

What are the side effects of class II anti-arrhythmic drugs?

A

Bronchospasm

Hypotension

23
Q

What are some examples of class III anti-arrhythmic drugs?

A

Amiodarone

Sotalol

24
Q

What is amiodarone used for?

A

Effective for most arrhythmias

25
Q

What are some side effects of amiodarone?

A
Pulmonary fibrosis 
Hepatic injury 
Inc LDL 
Thyroid disease 
Photosensitivity
26
Q

What is sotalol used for?

A

Supraventricular and ventricular tachycardia

27
Q

What are some side effects of sotalol?

A

Proarrhythmic
Fatigue
Insomnia

28
Q

What are some examples of class IV anti-arrhythmic drugs?

A

Verapamil

Diltiazem

29
Q

What are some uses of class IV anti-arrhythmic agents?

A

Control ventricles in supraventricular tachycardia

30
Q

What are some side effects of class IV anti-arrhythmic drugs?

A

Can get asystole if also using a β blocker

GI upset - constipation

31
Q

What is the MOA of adenosine as an anti-arrhythmic drug?

A

Slows AV conduction

Activates K+ channels => hyperpolarisation => decrease Ca2+ current => inc refractory period

32
Q

What is adenosine as an anti-arrhythmic used for?

A

Convert re-entrant supraventricular arrhythmias

Diagnosis of coronary artery disease

33
Q

What is the MOA of ivabradine as an anti-arrhythmic?

A

Blocks funny current in sinus node

Therefore slows sinus node w/o affecting BP

34
Q

What are some uses for ivabradine?

A

Reduce sinus tachycardia

Reduce HR in heart failure and angina - avoids BP drop

35
Q

What is the MOA of digoxin?

A

Enhances vagal activity

Slows AV conduction and slows HR

36
Q

What is digoxin used for?

A

Reduces ventricular rates in atrial fibrillation or flutter

37
Q

What is the MOA of atropine?

A

Selective muscarinic antagonist

Blocks vagal activity to speed AV conduction and increase HR

38
Q

What is a use of atropine?

A

Treats vagal bradycardia

39
Q

What drugs are used in AF to control rate and rhythm?

A

Rate control:
Bisoprolol, verapamil, diltiazem

Rhythm control:
Sotalol, flecainide with bisoprolol, amiodarone

40
Q

What drugs are used to treat WPW?

A

Flecainide

Amiodarone

41
Q

What drugs are used in re-entrant SVT?

A

Acute (IV)
Adenosine, verapamil, flecainide

Chronic (oral) 
Bisoprolol, flecainide 
Sotalol
Flecainide, procainamide
Amiodarone
42
Q

What drugs are used for ectopic beats?

A

First line: bisoprolol

Flecainide, sotalol, amiodarone

43
Q

What drugs are used to treat sinus tachycardia?

A

Ivabradine

Bisoprolol, verapamil