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Several types of medication can help control or resolve an arrhythmia.
The classification scheme most commonly in use today is the eponymously titled Vaughan Williams classification.
The basis of this classification is the grouping of agents according to their general effect, the Vaughan Williams classification remains in widespread use and is requisite knowledge for those working in the field of cardiac electrophysiology.
Class I: Fast sodium (Na) channel blockers
Ia -Quinidine, procainamide, disopyramide (depress phase 0, prolonging repolarization)
Ib -Lidocaine, phenytoin, mexiletine (depress phase 0 selectively in abnormal/ischemic tissue, shorten repolarization)
Ic -Flecainide, propafenone, moricizine (markedly depress phase 0, minimal effect on repolarization)
Class II: Beta blockers (partial list)
Propranolol (decreases slope of phase 4)
Esmolol (decreases slope of phase 4)
Timolol (decreases slope of phase 4)
Metoprolol (decreases slope of phase 4)
Atenolol (decreases slope of phase 4)
Class III: Potassium (K) channel blockers
Amiodarone (prolongs phase 3; also acts on phases 1, 2, and 4)
Sotalol (prolongs phase 3, decreases slope of phase 4)
Ibutilide (prolongs phase 3)
Dofetilide (prolongs phase 3)
Class IV: Slow calcium (Ca) channel blockers
Verapamil (prolongs phase 2)
Diltiazem (prolongs phase 2)
Class V: Variable mechanism
Adenosine
Digoxin
Magnesium sulfate
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