Antiarrhythmics Classification (Vaughan Williams)

Understand the conducting system of heart, cardiac action potential and pacemaker action potential.

Mnemonic to remember Vaughan Williams classification for anti-arrhythmic – Some Block Potassium Channel DAAM!

MnemonicClassMechanism of actionCommentsExampleUse
SomeIASodium channel blocker (moderate)
Intermediate action
Moderate ↓ phase 0 slope
↑ EFR & AP duration
Additional class III action
Quinidine, Procainamide, DisopyramideVentricular arrhythmias, WPW (procainamide)
IBSodium channel blocker (weak)
Fast action
Small ↓ phase 0 slope
↓ EFR & AP duration
Lidocaine, MexiletineVT
ICSodium channel blocker (strong)
Slow action
Pronounced ↓ phase 0 slope
= EFR & AP duration
Flecainide, PropafenoneParoxysmal AF, recurrent SVT
BlockIIBeta blocker↓ phase 4 slope in nodes (pacemaker potential)
Prolong AV node repolarization
Atenolol, Bisoprolol, Carvedilol, Esmolol, Metoprolol, Propranolol, SotalolRecurrent tachyarrhythmias
PotassiumIIIPotassium channel blockerDelay phase 3 (repolarization)Amiodarone (also class I, II & IV action), Sotalol (also class II action), Dofetilide, IbutilideAtrial fibrillation & flutter, Ventricular tachycardia
ChannelIVCalcium channel blockerProlongs phase 2
↓ slope phase 0 & 4 in node (pacemaker potential)
Prolong AV node repolarization
Verapamil, DiltiazemParoxysmal SVT, AF with RVR
DAAMV/OthersDirect nodal inhibitionDigoxin
Magensium sulphate
SVT (Adenosine), Torsades de pointes (Magnesium), Rate control in AF (Digoxin)

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