Anti-arrhythmic Drugs

Question 1

what are the classes of anti-arrhythmic drugs?

Answer 1

1, 2, 3 and 4

Question 2

name a class 1a anti-arrhythmic

Answer 2

procainamide

Question 3

name a class 1b anti-arrhythmic

Answer 3

lidocaine

Question 4

name a class 1c anti-arrhythmic

Answer 4

flecainide

Question 5

name a class 2 anti-arrhythmic

Answer 5

bisoprolol

propranolol

Question 6

name a class 3 anti-arrhythmic

Answer 6

amiodarone

sotalol

Question 7

name a class 4 anti-arrhythmic

Answer 7

verapamil

diltiazem

Question 8

what is the mechanism of action of class 1 anti-arrhythmics?

Answer 8

block Na channels in non-nodal cardiomyocytes

therefore slowing upstroke of action potential, slowing conduction of AP and increase refractory period

Question 9

what is the difference between the sub-classes of type 1 anti-arrhythmics?

Answer 9

block K channels differently
1A>1C>1B
(KC blockade increases refractory period)

Question 10

what are the side effects of Class 1 anti-arrhythmics?

Answer 10

pro-arrhythmic

dizziness

Question 11

what is the mechanism of action of class 2 anti-arrhythmic drugs?

Answer 11

block beta 1 receptors in the AV node, slowing transmission of AP from atria to ventricles

Question 12

what are the side effects of class 2 anti-arrhythmics?

Answer 12

bronchospasm (beta 2 adrenoceptors in lungs)

hypotension

Question 13

name 2 class 3 anti-arrhythmic drugs

Answer 13

amiodarone

sotalol

Question 14

what is the mechanism of action of class 3 anti-arhythmic drugs?

Answer 14

block K+ channels in all cardiac tissue, causing increased refractory period in nodal and non-nodal cardiomyocytes causing decreased speed of AP conduction

Question 15

what are the side effects of class 3 anti-arrhythmics?

Answer 15

pro-arrhythmic

Question 16

what are some serious side effects of amiodarone?

Answer 16

pulmonary fibres

bradycardia and AV block, so contra-indicated in patients with heart block os SAN dysfunction

Question 17

name 2 class 4 anti-arrhythmic drugs

Answer 17

verapamil

diltiazem

Question 18

what is the mechanism of action of class 4 anti-arryhythmic drugs?

Answer 18

calcium channel blockers in SAN and AVN - prevents upstroke of nodal action potential
slows heart rate

Question 19

what are the side effects of class 4 anti-arrhythmic drugs?

Answer 19

bradycardia

hypotension

Question 20

what drug group does digoxin belong to?

Answer 20

cardiac glycoside

Question 21

what is the mechanism of action of digoxin as an anti-arrhythmic?

Answer 21

inhibits NaK ATPasein all cardiac tissue

Na and Ca accumulate intracellularly causing slowed SAN and AVN conduction, slowing heart rate

Question 22

what are the side effects of digoxin?

Answer 22

arrhythmias
blurred/yellow vision
dizziness
eosinophilia
rash
vomiting

Question 23

what is the mechanism of action of adenosine as an anti-arrhythmic drug?

Answer 23

activate A1 receptors in the heart which are GiPCRs

cause cell hyper polarisation in SAN and AVN, slowing AV conduction

Question 24

what are the side effects of adenosine?

Answer 24

arrhythmia
AV block
dizziness
flushing
headache
nausea

Question 25

describe the NICE guidance for treatment of acute atrial fibrillation

Answer 25

1. electrical cardioversion if life-threatening haemodynamic instability 2. if pharmacological cardioversion is decided - use flecainide (1c) or amiodarone (3) when there is no evidence of IHD or structural disease (amiodarone if there is disease) 3. anticoagulation

Question 26

describe the NICE guidance for long-term treatment of atrial fibrillation

Answer 26

1. rate control - beta blocker (other than sotalol) or CCB as monotherapy (if doesn't work, combine with diltiazem (4) or digoxin 2. anticoagulation