A simple and easy way to remember your anti-arrhythmic agents. Mnemonics: Some Block Potassium Channels. Vaughn-Williams Classification | Class I: Sodium Channel Blockers. Class II: Beta-Blockers. Class III: Potassium Channel Blockers. Class IV: Calcium Channel Blockers. Class I Class Ia: Causes moderate degree blockage of fast sodium channels. Drugs include quinidine, procainamide, and disopyramide. Causes... Continue Reading →