Antiarrhythmikum is a generic term for drugs that can be used for treatment of cardiac arrhythmias. Traditionally, Antiarrhythmics after their Electro physiological mechanisms are divided into four classes (I to IV according to Vaughan / Williams).

Vaughan / Williams Classification

1970 published E.M. Vaughan and D.M. Williams still used today classification of antiarrhythmics:

* Class I (sodium channel blockers)
* Class Ia (with prolongation of action potential), including quinidine, procainamide, and disopyramide Ajmalin,
* Class Ib (with shortening of the action potential), including lidocaine, phenytoin and Mexiletin,
* Class Ic (no effect on the duration of the action potential), including flecainide and propafenone,
* Class II (beta blockers), including Metoprolol, Nebivolol and Bisoprolol,
* Class III (potassium channel blockers), including amiodarone, Dronedaron, Sotalol and the unauthorized Bretylium,
* Class IV (calcium channel blockers), including verapamil and diltiazem.

The usefulness of this classification has since been widely questioned, because some properties of several classes of antiarrhythmics and different, especially new agents do not fit into the scheme. Amiodarone and Dronedaron, for example, have properties of all four classes. For substances that are classified into classes I to IV eingruppiert could be followed later by some authors

* Class V (Various)

For Digitalispräparate, adenosine, Ivabradin and others added.