From the Guidelines
Anti-arrhythmia agents can be classified into four main types:
- Type I: Fast sodium channel blockers, which include IA (e.g., Disopyramide, Procainamide, Quinidine), IB (e.g., Lidocaine, Mexiletine), and IC (e.g., Flecainide, Propafenone)
- Type II: Beta blockers (e.g., Beta-blockers like propranolol)
- Type III: Repolarization potassium current blockers (e.g., Amiodarone, Sotalol, Dofetilide)
- Type IV: Calcium channel antagonists (e.g., Verapamil, Diltiazem) 1, 2, 3
Key Characteristics of Each Type
- Type I: Subclassified into IA, IB, and IC, with different effects on cardiac conduction and contraction
- Type II: Beta blockers, which reduce sympathetic tone and slow heart rate
- Type III: Prolong repolarization, increasing the risk of torsades de pointes
- Type IV: Calcium channel blockers, which reduce calcium influx and slow heart rate
Clinical Use
- The choice of anti-arrhythmia agent depends on the underlying heart disease, the type of arrhythmia, and the patient's symptoms and medical history 4, 5
- Each type of anti-arrhythmia agent has its own set of indications, contraindications, and potential side effects, which must be carefully considered in clinical practice 1
From the Research
Types of Anti-Arrhythmia Agents
The types of anti-arrhythmia agents can be classified into four main classes according to the Vaughan Williams classification, which is based on their effects on various ion channels [ 6, 7, 8, 9 ]. These classes are:
- Class I: Antiarrhythmic agents that block the fast-inward sodium channel on myocardium, including subclassifications such as Class Ia, Class Ib, and Class Ic [ 6, 7, 8, 9 ].
- Class II: Antisympathetic drugs, particularly the b-adrenoceptor blockers, which are generally safe agents [ 6, 7 ].
- Class III: Antiarrhythmic agents that prolong action potential duration and repolarization, including drugs such as amiodarone and sotalol [ 6, 7, 8, 9 ].
- Class IV: Calcium channel blockers, including verapamil and diltiazem, which are normally monitored by haemodynamic effects [ 6, 7 ].
Other Anti-Arrhythmia Agents
In addition to the four main classes, there are other anti-arrhythmia agents that do not fall neatly into the Vaughan Williams classification, including:
- Digoxin: A drug with unique antiarrhythmic properties, which can be useful in the management of selected patients [ 6, 7 ].
- Adenosine: A drug with unique antiarrhythmic properties, which can be useful in the management of selected patients [ 7 ].
- Perhexiline: A drug that can be useful for monitoring the administration and safety of antiarrhythmic agents [ 6 ].