(Redirected from Antiarrhythmic)


Class Known as Examples Mechanism Clinical uses
Ia fast-channel blockers-Affect QRS complex (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 (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 (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 beta blocking
Propranolol also shows some class I action
  • decrease Myocardial infarction mortality
  • prevent recurrence of Tachyarrhythmias

K+ channel blocker

Sotalol is also a β-blocker

Amiodarone has Class I, II, and III activity

IV slow-channel blockers Ca2+ channel blocker
  • prevent recurrence of Paroxysmal supraventricular tachycardia
  • reduce Ventricular rate in patients with Atrial fibrillation
V Work by other or unknown mechanisms (Direct nodal inhibition).

Used in supraventricular arrhythmias,

Or in the case of magnesium sulfate, used in torsade de pointes.

See Also


  • Katzung & Trevor's Pharmacology