What are the Vaughan Williams classifications?

Vaughan Williams classification

  • Class I agents interfere with the sodium (Na+) channel.
  • Class II agents are anti-sympathetic nervous system agents.
  • Class III agents affect potassium (K+) efflux.
  • Class IV agents affect calcium channels and the AV node.
  • Class V agents work by other or unknown mechanisms.

How does IB antiarrhythmics work?

Class IB antiarrhythmics suppress automaticity of conduction tissue by increasing the electrical stimulation threshold of the ventricle and His-Purkinje system and inhibiting spontaneous depolarization of the ventricles during diastole through a direct action on the tissues.

What are the classification of antiarrhythmic?

Classification of antiarrhythmic therapies

Class Mechanism of action
Class II – beta-blockers Block catecholamines at beta1-adrenoceptors prolonging repolarisation
Class III – potassium-channel blockers Block K+ efflux
Class IV – calcium-channel blockers Block Ca2+ influx
Class V – other agents Various mechanisms

What is most common side effects of antiarrhythmic therapy?

Common side effects caused by antiarrhythmics include:

  • possible issues with your liver, kidneys, thyroid or lungs (these will be monitored by your health professional)
  • tiredness.
  • nausea (feeling sick)
  • shortness of breath (if this gets so bad that you feel unsafe, seek medical attention immediately).

In which class of the Vaughan Williams classification system of Antidysrhythmic medications does quinidine belong?


Class I Drug Actions: Blocks sodium (Na+) channels in fast potential Slows impulse conduction in atria and ventricles Delays repolarization
Class IA Drugs: Quinidine Procainamide
Class IB Drugs: Lidocaine Mexiletine Phenytoin

What is the mechanism of action for Class II antiarrhythmics?

Class II antiarrhythmics inhibit beta-adrenergic activation of adenylate cyclase, reduce intracellular cAMP levels, and therefore reduce Ca2+ influx, resulting in decreased sinoatrial node (SAN) pacing and triggered activity and increase in atrioventricular node (AVN) conduction time and refractoriness.

What are Class 1A antiarrhythmics used for?

A class 1A antiarrhythmic agent used to treat life-threatening ventricular arrhythmias. A medication used to restore normal sinus rhythm, treat atrial fibrillation and flutter, and treat ventricular arrhythmias.

What are the four classes of antiarrhythmic medication?

Antiarrhythmic drug classes:

  • Class I – Sodium-channel blockers.
  • Class II – Beta-blockers.
  • Class III – Potassium-channel blockers.
  • Class IV – Calcium-channel blockers.
  • Miscellaneous – adenosine. – electrolyte supplement (magnesium and potassium salts) – digitalis compounds (cardiac glycosides)

What is the most effective treatment for atrial fibrillation?

Heart rate medicines: The most common way to treat atrial fibrillation is with drugs that control your heartbeat. These slow your rapid heart rate so your heart can pump better. You may need other drugs. Some are called beta-blockers.

What are antiarrhythmics used for?

Antiarrhythmic medications prevent and treat abnormal heartbeats (arrhythmias). Problems with your heart’s rhythm are caused by a disruption in the heart’s electrical system. A drug called atropine may be prescribed if your heart beats too slowly (bradycardia).

In which class of Vaughan Williams classification system of Antidysrhythmic medications does amiodarone belong?

Class III Drugs: Amiodarone. Ibutilide. Sotalol (also a β-blocker)