cvs - anti-arrhythmic drugs

Question 1

moa of class I

Answer 1

Na+ channel blocker → ↓ excitability and conduction velocity

Question 2

clinical use of class I

Answer 2

Ventricular and supraventricular tachycardia

Question 3

name a class IA drug

Answer 3

procainamide

Question 4

changes to ERP and APD in class IA

Answer 4

both ↑

Question 5

name a class IB drug

Answer 5

lidocaine

Question 6

changes to ERP and APD in class IB

Answer 6

ERP no change , APD ↓

Question 7

name a class IC drug

Answer 7

flecainide

Question 8

changes to ERP and APD in class IC

Answer 8

both no change

Question 9

moa of procainamide

Answer 9

• Slows phase 0 depol
• Reduces conductivity and automaticity

Question 10

moa of lidocaine

Answer 10

• Shorten phase 3 repol
• Slow phase 0 depol
• Reduces automaticity

Question 11

moa of flecainide

Answer 11

• Slows phase 0 depol
• Shorten phase 3 repol
• Reduces conductivity and automaticity

Question 12

clinical use of flecainide

Answer 12

Refractory ventricular tachycardia → progress to vfib

Question 13

moa of class II

Answer 13

• β-blockers → ↓ HR and contractility
• Suppress phase 4 depol
• Reduces automaticity
• Prolong AV conduction

Question 14

name 2 eg of class II

Answer 14

1. Metoprolol succinate
2. Bisoprolol

Question 15

changes to ERP and APD in class II

Answer 15

both no change

Question 16

clinical uses of class II

Answer 16

• Tachycardia due to sym activation
• AV nodal reentrant tachycardia
• Atrial fibrillation
• Reduces sudden arrhythmic death post-MI

Question 17

adverse effects of class II

Answer 17

• Bradycardia
• AV block
• Bronchospasm

Question 18

name a class III

Answer 18

Amiodarone

Question 19

moa of class III

Answer 19

• K+ channel blockers → prolong repol by inhibiting K+ efflux
• Prolongs phase 3 repol (due to blockade of Ikr and Iks)

Question 20

changes to ERP and APD in class III

Answer 20

both ↑

Question 21

clinical use of class III

Answer 21

• Atrial fibrillation
• Prevent reentrant ventricular tachycardia

Question 22

adverse effects of class III

Answer 22

• bradycardia
• heart block
• thyroid dysfunc

Question 23

moa of class IV

Answer 23

• Non-DHP Ca2+ channel blockers → ↓ Ca2+ influx at SA and AV node → ↓HR
• Prolongs phase 4 depol
• Reduces conductivity

Question 24

name 2 class IV

Answer 24

1. Verapamil
2. Diltiazem

Question 25

changes to ERP and APD in class IV

Answer 25

both ↑

Question 26

clinical uses of class IV

Answer 26

- Supraventricular tachycardia - Hypertension - Angina

Question 27

contraindication for class IV

Answer 27

- depressed cardiac func - hypotension

Question 28

moa of adenosine

Answer 28

- Suppression of AV nodal conduction, increase AV nodal refractory period → stimulates cardiac K+ channel + inhibit Ca2+ current

Question 29

clinical use of adenosine

Answer 29

- emergency supraventricular tachycardia

Question 30

adverse effects of adenosine

Answer 30

- Flushing - SOB, chest burning - AV block, afib - Headache, hypotension