What are classes of antiarrhythmatic drugs?

Class I (Quinidine, Lidcaine, Flecainide - Sodium action) Class II (Esmolol, Metoprolol, Propanolol - beta blockers) Class III (Amiodarone, Sotalol - Potassium) Class IV (Verapamil, Diltiazem - Ca channel blockers)