Class Ic drugs are used for suppression of Atrial fibrillation Atrial flutter Atrial premature beats Supraventricular tachycardia Ventricular fibrillation Ventricular premature beats Ventricular tachycardias Class II Antiarrhythmic Drugs Class II antiarrhythmic drugs are the Beta-blockers Beta-blockers affect predominantly slow-channel tissues (sinoatrial and atrioventricular nodes), where they decrease rate of automaticity, slow conduction velocity, and prolong refractoriness.