Anti-arrhythmia drugs:

Question 1

Class 1A (quinidine)

Answer 1

Na channel blocker, decreases conduction and increases the refractory period.

Question 2

Class 1B (lidocaine)

Answer 2

Na channel blocker, increases threshold but no change in phase 0.

Question 3

Class 1C (flecainide)

Answer 3

Na channel blocker, reduces phase 0.

Question 4

Class 2 (atenolol)

Answer 4

beta blocker, blocks beta 1 receptors to increase the AP duration and refractory.

Question 5

Class 3 (amiodarone)

Answer 5

potassium channel blocker, increases refractory period and decreases speed of AV conduction.

Question 6

Class 4 (verapamil)

Answer 6

calcium channel blocker, increases refractory of AVN and changes slope in SA node, to decrease heart rate.

Question 7

Adenosine

Answer 7

activates K currents in SAN and AVN leading to hyperpolarisation and increases the refractory period and reduces AV conduction.

Question 8

Digoxin

Answer 8

enhances vagal activity on heart rate.

Question 9

Atropine

Answer 9

muscarinic antagonist that blocks vagal activity.