ANTIARRHYTHMIC AGENTS (antidysrhythmic agents) are used to treat a number of heart conditions characterized by irregularities of heart beat. They have been classified under the Vaughan Williams Scheme, though not all clinically used agents neatly fit these classes.
Class I (which has a number of subtypes) is mainly used to treat atrial and ventricular tachycardias, and contains a number of SODIUM-CHANNEL BLOCKERS, e.g. disopyramide, flecainide, lignocaine, procainamide and quinidine.
In addition to drugs in these classes, others may be used for certain arrhythmias. Digoxin may be used for treatment of atrial fibrillation, adrenaline for asystolic cardiac arrest, atropine for sinus bradycardia, methacholine (rarely) for supraventricular tachycardia, magnesium salts for ventricular arrhythmias, and calcium salts for ventricular arrhythmia due to hyperkalaemia.