Ch. 13 - Antiarrhythmic Drugs

Question 1

Non-pharmacological approaches to arrhythmias

Answer 1

Pacemakers
Implantable defibrillators
Ablation of an aberrant conduction pathway

Question 2

Class I drugs MOA:

Groups?

Answer 2

Sodium channel blockers –> !- rate of rise of phase 0 of the action potential and suppress automaticity of purkinje fibers and His bundle

A, B, C

Question 3

Class IA drugs?

MOA?

Answer 3

Slow rate of rise of phase 0 and prolong refractory period of ventricle

Procainamide
Quinidine
Disopyramide

Question 4

Class IB drugs?

MOA?

Answer 4

Less effect on phase 0, but shorten action potential duration and refractory period

Lidocaine
Mexilentine
Phenytoin
Tocainide

Question 5

Class IC drugs?

MOA?

Answer 5

Greatest effect on phase 0 and less effect on refractory period

Flecainide
Propafenone

Question 6

Class IA uses?

Answer 6

All-purpose antiarrhythmics

Quinidine ~ quinine = antimalarial actions

Question 7

Class IB uses?

Answer 7

“Drug of choice”
Tx of ventricular arrhythmias (ventricular tachycardia, ventricular fi brillation, and ventricular ectopy)

NOT effective in the atrial (supraventricular) arrhythmias

Question 8

Class IC uses?

Answer 8

Po

Chronic suppression of ventricular arrhythmias (IB was acute)

Question 9

Moricizine

Answer 9

Features of all three subclasses

The action of it on sodium receptor is Use-dependent (the more the channel is used the more it is blocked)

Question 10

Class II drugs

Answer 10

Beta-blockers

Uses: conduction through SA and AV nodes are slowed and refractory period is increased

For tx tachyarrhythmias from increased sympathetic activity

Most common: propranolol

Question 11

Class II drugs MOA?

Drugs?

Answer 11

Prolong depolarization (potassium channel blockers), don’t alter the phase 0 or resting membrane potential

Bretylium
Amiodarone
Dronedarone
Dofetilide
Ibutilide
Sotalol

Question 12

Amiodrone uses?

Answer 12

Cardiac arrest and Vtach Vfib