EM Podcasts

Overview table

Class	Known as	Examples	Mechanism	Clinical uses
Ia	fast-channel blockers-Affect QRS complex	Quinidine Procainamide Disopyramide	(Na+) channel block (intermediate association/dissociation)	Ventricular arrhythmias prevention of paroxysmal Recurrent atrial fibrillation (triggered by Vagus nerve overactivity) procainamide in Wolf Parkinson White (WPW)
Ib- Do not affect QRS complex		Lidocaine Phenytoin Mexiletine Tocainide	(Na+) channel block (fast association/dissociation)	treatment and prevention during and immediately after Myocardial infarction, though this practice is now discouraged given the increased risk of Asystole Ventricular tachycardia Atrial fibrillation
Ic		Flecainide Propafenone Moricizine	(Na+) channel block (slow association/dissociation)	prevents Paroxysmal atrial fibrillation treats Recurrent tachyarrhythmias of abnormal conduction system. contraindicated immediately post-myocardial infarction.
II	Beta-blockers	Propranolol Esmolol Timolol Metoprolol Atenolol Bisoprolol	beta blocking Propranolol also shows some class I action	decrease Myocardial infarction mortality prevent recurrence of Tachyarrhythmias
III		Amiodarone Sotalol Ibutilide Dofetilide Dronedarone E-4031	K+ channel blocker Sotalol is also a beta blocker Amiodarone has Class I, II, and III activity	In Wolf Parkinson White (WPW) (sotalol:) Ventricular tachycardias and Atrial fibrillation (Ibutilide:) Atrial flutter and Atrial fibrillation
IV	slow-channel blockers	Verapamil Diltiazem	Ca2+ channel blocker	prevent recurrence of Paroxysmal supraventricular tachycardia reduce Ventricular rate in patients with Atrial fibrillation
V		Adenosine Digoxin Magnesium Sulfate	Work by other or unknown mechanisms (Direct nodal inhibition).	Used in supraventricular arrhythmias, Or in the case of Magnesium Sulfate, used in Torsade de Pointe.