Cardiac Arrhythmia Drugs

Question 1

What is the MoA of Class 1 AADs?

Answer 1

Block the sodium channel -> decrease the phase 0 upstroke
Slow conduction in myocytes
Decrease AP duration

Question 2

What is the MoA of Class 2 AADs?

Answer 2

Beta-blockers
Act on phase 4
Decrease the gradient of the funny current to decrease HR
Decrease depolarisation in myocytes

Question 3

What is the MoA of Class 3 AADs?

Answer 3

Potassium channel blockers
Act on phase 3
Increase AP duration (and end refractory period)

Question 4

What is the MoA of Class 4 AADs?

Answer 4

Calcium channel blocker
Acts on phase 2
Decrease depolarisation
Decrease conduction
Increase AV node refractory period

Question 5

What are the effects of Class 1a AADs?

Answer 5

Effects on cardiac activity: decrease conduction, increase refractory period, decrease automacity, increase threshold

ECG effects: increase QRS, +/- PR, increase QT

Question 6

What are the effects of Class 1b AADs?

Answer 6

Effects on cardiac activity: in fast beating or ischaemic tissue there is a decrease in phase 0 conduction, increase threshold, decrease AP depolarisation

ECG effects: Increase in QRS in fast beating or ischaemic tissue

Question 7

What are the effects of Class 1c AADs?

Answer 7

Effects on cardiac activity: decrease phase 0, decrease automacity (increase threshold), increase AP duration, increase refractory period

ECG effects: increase PR, QRS and QT interval

Question 8

What are the uses of class 1a AADs?

Answer 8

Quinidine - maintains sinus rhythm in AF

Procainamide - acute IV arrhythmias

Question 9

What are the side effects of class 1 AADs?

Answer 9

Hypotension
Proarrhytmic e.g. Torsades de Points (increased QT)
GI effects
Lupus-like syndrome
DIzzines, confusion, insomnia, seizure

Question 10

Examples of class 1b AADs?

Answer 10

Lidocaine - IV

Mexiletine - oral

Question 11

Uses of class 2 AADs?

Answer 11

Acute ventricular tachycardia, especially during ischaemia

Question 12

Side effects of class 1b AADs?

Answer 12

Proarrhythmic
Dizziness, drowsiness
Abdominal upset

Question 13

Uses of class 1c AADs?

Answer 13

AF
Ectopic beats
WPW Syndrome

Question 14

Side effects of class 1c AADs?

Answer 14

Proarrhytmic - sudden death especially with chronic use and structural heart disease
Increased ventricular response to supraventricular arrhythmia
CNS and GI effects

Question 15

Examples of class 2 AADs?

Answer 15

Propanolol - oral and IV

Metoprolol - oral and (5mg) IV

Question 16

Effects of Class 2 AADs?

Answer 16

Cardiac effects: increase AP depolarisation and refractory period to decrease AVN conduction, decrease phase 4 depolarisation

ECG effects: increase PR and decrease HR

Question 17

Uses of Class 2 AADs?

Answer 17

Sinus and catecholamine dependent tachycardia
Prevent re-entry arrhythmias at AVN
Protect ventricles from increased atrial rates

Question 18

Side effects of Class 2 AADs?

Answer 18

Bronchospasm (!Asthma)
Hypotension
CI: partial AV block and heart failure

Question 19

Effects of Amiodarone? (Class 3 AAD)

Answer 19

Cardiac effects: increase refractory period, AP depolarisation and threshold, decrease phase 0, conduction, phase 4 and the speed of AVN conduction

ECG effects: increase PR, QRS, QT, decrease HR

Question 20

Uses of Amiodarone? (Class 3 AAD)

Answer 20

Most arrhythmias

Question 21

Side effects of Amiodarone? (Class 3 AAD)

Answer 21

Serious and increase with time
Pulmonary fibrosis
Hepatic injury
Increase LDL 
Thyroid disease
Photosensitivity
Optic neuritis
!May need to decrease digoxin and monitor warfarin

Question 22

Effects of Sotalol? (Class 3 AAD)

Answer 22

Cardiac effects: increase AP depolarisation and refractory period, slow phase 4, decrease AV conduction

ECG effects: increase QT, decrease HR

Question 23

Uses of Sotalol? (Class 3 AAD)

Answer 23

Supraventricular and ventricular tachycardia

Question 24

Side effects of Sotalol? (Class 3 AAD)

Answer 24

Proarrhythmia
Fatigue
Insomnia

Question 25

Examples of Class 4 AADs?

Answer 25

Verapamil - oral or IV

Diltiazem - oral

Question 26

Effects of Class 4 AADs?

Answer 26

Cardiac effects: decrease conduction through AVN, increase refractory conduction period in AVN, decrease in HR

ECG effects: increase PR, change in HR depending on BP

Question 27

Uses of Class 4 AADs?

Answer 27

Supraventricular tachycardia

Question 28

Side effects of Class 4 AADs?

Answer 28

GI problems
!Hypotension
Asystole if using beta-blocker

Question 29

MoA of Adenosine?

Answer 29

Binds to A1 receptors -> activates K+ currents in AVN and SAN -> decrease AP depolarisation -> hyperpolarisation -> decrease in HR

Decrease calcium ion currents -> increase refectory period in AVN -> decrease AVN conduction

Question 30

Uses of Adenosine?

Answer 30

Re-entrant supraventricular arrhythmias

Hypotension during surgery

Question 31

How is Adenosine administered?

Answer 31

Rapid IV bolus

Question 32

MoA of Vernakalant?

Answer 32

Blocks atrial specific K+ channels

Decrease atrial conduction and increase potency with increased HR

Question 33

How is Vernakalant administered?

Answer 33

IV bolus

Question 34

Side effects of Vernakalant?

Answer 34

Hypotension
AV block
Sneezing
Taste disturbances

Question 35

Uses of Vernakalant?

Answer 35

Acute AF

Question 36

How is Ivabradine administered?

Answer 36

Orally 2.5mg x2/day

Question 37

MoA of Ivabradine?

Answer 37

Blocks funny current in SAN -> decreased HR

Doesn’t decrease BP

Question 38

Uses of Ivabradine?

Answer 38

Decrease inappropriate sinus tachycardia

Decrease HR in HF and angina

Question 39

Side effects of Ivabradine?

Answer 39

Flashing lights

CI: pregnancy

Question 40

MoA of Digoxin?

Answer 40

Increase vagal activity
Blocks NaKATPase
Decrease HR

Question 41

Uses of Digoxin?

Answer 41

Decrease ventricular rates in AF and flutter

Question 42

MoA of Atropine?

Answer 42

Selective muscarinic antagonist

Blocks vagal activity -> increase AVN conduction and increase HR

Question 43

Uses of Atropine?

Answer 43

Vagal bradycardia