CVS - antiarrhythmia

Question 1

6 classes of antiarrhythmic drugs

Answer 1

IA
IB
IC
II
III
IV

Question 2

Class IA drug

Answer 2

Procainamide

Question 3

Class IA MOA

Answer 3

Na+ channel blocker
slow phase 0 depolarisation 
increase ERP (effective refractory period) and APD (action potential duration) 
decrease conduction and automaticity

Question 4

Class IB drug

Answer 4

Lidocaine

Question 5

Class IB MOA

Answer 5

Na+ channel blocker
shorten phase 3 repolarisation
ERP unchanged, decrease APD
decrease automaticity

Question 6

Class IC drug

Answer 6

Flecainide

Question 7

Class II MOA

Answer 7

b-adrenoreceptor blocker
suppress phase 4 depolarisation
ERP unchanged

Question 8

Flecainide clinical use and ADR

Answer 8

refractory ventricular tachycardia progressing to VF

Question 9

Class II drug

Answer 9

propanolol

Question 10

Class II MOA

Answer 10

b-adrenoreceptor blocker
suppress phase 4 depolarisation
ERP unchanged

Question 11

Propanolol clinical use

Answer 11

tachyarrythmias caused by sympathetic stimulation
atrial flutter and fib
AV nodal re-entrant tachycardia??
unlike other anti-arrhythmias, it reduces mortality (rest increases mortality)

Question 12

Class III drug

Answer 12

Amiodarone

Question 13

Class III (Amiodarone) MOA

Answer 13

K+ channel blocker
prolong phase 3 repolarisation
increase ERP

blocks Na+, Ca2+ channels, and adrenergic receptor

Question 14

Amiodarone clinical use and ADR

Answer 14

maintain normal sinus rhythm in pts with AF
prevent recurrent ventricular tachycardia
ADR: symptomatic bradycardia and heart block

Question 15

Class IV drug

Answer 15

verapamil

Question 16

Class IV MOA

Answer 16

Ca2+ channel blocker
prolongs action potential
increase ERP and ADP
decrease automaticity and slow conduction

Question 17

verapamil clinical use and ADR + CI

Answer 17

supraventricular tachycardia (above bundle of His - SA/AV node)
hypertension
angina pect
ADR: hypotension
CI: pts with depressed cardiac fn