Mechanism of Action of AA

Question 1

How are anti-arrhythmic drugs classified?

Answer 1

I- Na channel blockers
II- B blockers
III- AP prolonging drugs
IV- Ca channel blockers
V- Others

Question 2

Examples of class 3 AA

Answer 2

amiodarone, sotalol

Question 3

explain the effects that each class 1 AA has on AP lengh

Answer 3

1A: prolong
1B: shorten
1C: no major effect

Question 4

what are class 1B AA for

Answer 4

acute ventricular tachycardia

Question 5

what is the MOA of amiodarone and sotalol?

Answer 5

block K conductances and therefore prolong AP

Question 6

what is amiodarone used for?

Answer 6

atrial fibrillation and atrial flutter, and ventricular tachyarrythmia

Question 7

how do CCB work?

Answer 7

they depress spontaneous depolarization in SAN, and decrease AVN conduction. They have a negative inotropic effect on myocardium

Question 8

what effects does digoxin have?

Answer 8

negative chronotropic and negative dromotropic effects. Positive inotrope

Question 9

how does digoxin work?

Answer 9

it stimulates the vagus nerve as it is a cardiac glycoside (note that it mostly affects the atria and thus is used for treatment of A fib and A flutter)

Question 10

what is ivabradine and how does it work?

Answer 10

it directly reduces HR by targeting the SAN (and inhibiting If). it is used for angina pectoris and HF.

Question 11

what drugs are used for bradyarrythmias?

Answer 11

anti-muscarinics like atropine, ipratropium. And Beta-sympathomimetics