<prompt> Quinidine belongs to class antiarrhythmic drug isClass IClass IIClass IIIClass IV  <response>: i.e. class I: 510-17-KDT 6th 367-68-MDT-l1ANTIARRHYTHMIC DRUGSClass Ia Sodium channel blockers Depress phase O depolarization Slow conduction, prolong repolarization Drugs Quinidine, Procainamide, Disopyramide, MoricizineClass Ib Shorten repolarization Drugs Lidocaine, MexiletineClass IC Depress phase O repolarization, slow conduction Propafenone is a week calcium channel blocker and b-blockers and prolongs action potential and refractionariness Drugs Flecainide, PropafenoneClass II b-blockers Slow AV conduction Drugs Esmolol, Propanolol, MetoprololClass III Prolong action potential Prolong repolarization and ERP Drug Amiodarone, Bretylium also class II Dofetilide, Ibutilide, Dronedarone, SotalolClass IV Calcium Channel blockers Drugs Verapamil, diltiazem 