What are the 4 classes of antiarrhythmic medication?
There are four classes of antiarrhythmics, based on the Vaughan-Williams (VW) classification system:
- Class I. Sodium channel blockers. These drugs prevent sodium from getting through cell membranes. This can slow electrical impulses in the heart muscle. Examples include disopyramide, flecainide, mexiletine, propafenone and quinidine.
- Class II. Beta blockers. These drugs slow down the heart rate. Examples include acebutolol, atenolol, bisoprolol, metoprolol, nadolol and propranolol.
- Class III. Potassium channel blockers. These drugs prevent potassium from getting through cell membranes. This slows down electrical impulses in the heart’s cells. Examples include amiodarone, bretylium, dofetilide, dronedarone, ibutilide and sotalol.
- Class IV. Nondihydropyridine calcium channel blockers. These drugs block calcium channels in heart muscle. This can decrease heart rate and contractions. Examples include diltiazem and verapamil.
Other antiarrhythmic drugs not included in the VW classification system include:
Adenosine. This medication can block or slow down electrical impulses at the atrioventricular node (AVN), between the upper and lower chambers of the heart.
Digoxin. This drug slows the heart rate and make it contracts more strongly.
Arrhythmia treatment also may involve other medications that are not antiarrhythmics, such as anticoagulants (blood thinners).
