Anti-Arrhythmics

Electrophysiology of cardiac muscle: the pathophysiological mechanisms responsible for the genesis of cardiac arrhythmias are not clearly understood. However, it is generally accepted that cardiac arrhythmias arise as the result of either of

1. Disorders of impulse formation and/ or
   1. Disorders of impulse conduction.

Pharmacotherapy of cardiac arrhythmias

Antiarrhythmic drugs are used to prevent or correct cardiac arrhythmias (tachyarrhythmias). Drugs used in the treatment of cardiac arrhythmias are traditionally classified into:

• Class (I):         Sodium channel blockers which include quinidine, lidocaine, phenytion, flecainide, etc.
• Class (II):        Beta adrenergic blockers which include propranolol, atenolol, etc. Class (III):  Potassium channel blockers e.g. amiodarone, bretylium.
• Class (IV):       Calcium channel blockers e.g. verapamil, etc. Class (V): Digitalis e.g.digoxin.