antiarrhythmic agent classes Flashcards
Class I
-Block Na+ channels to slow or block conduction and slow or abolish abnormal pacemakers
Class IA:
- Also block K+ channels to prolong refractory period
- Moderate Na+ channel blockade with K+ channel blockade
Class IB:
- Minimal effect on atrial tissues or AV conduction
- Mild Na+ channel blockade without K+ channel blockade
example of class IB drug?
Lidocaine
Class IC:
- markedly pro-arrhythmic
- marked Na+ channel blockade without K+ channel blockade
example of class IC drug?
Flecainide
Class II
Beta blockers that suppress abnormal pacemakers and slow AV conduction
example of class II drug?
metoprolol
Class III
Block K+ channels to delay phase 3 repolarization and increase refractory period
examples of class III drug?
amiodarone, sotalol
Class IV
Ca+ channel blockers (AV node) that prolong AV conduction to slow HR
Examples of class IV drug?
Verapamil, diltiazem
example of class IA drug?
procainamide
adenosine
suppresses nodal action potentials by hyperpolarizing this tissue and by reducing Ca++ current resulting in inhibition of AV nodal conduction and increased refractory period
Digoxin
possesses cardiac parasympathomimetic (activates PSNS) actions (vagal activation, acetylcholine) that can be used to treat rapid atrial or AV nodal arrhythmias
