Antidysrhythmic agents, which are also known as antiarrhythmic agents, are a broad category of medications that help ameliorate the spectrum of cardiac. The ultimate goal of antiarrhythmic drug therapy is to restore normal rhythm and conduction. When it is not possible to revert to normal sinus rhythm, drugs may. Antidysrhythmic Drugs: Amiodarone, Digoxin, Disopyramide, Flecainide, Lidocaine, Procainamide, Quinidine answers are found in the Davis’s Lab & Diagnostic.

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Arrhythmias generally arise as a result of abnormal impulse generation or abnormal conduction, or a combination of the two. Class IV agents are slow non-dihydropyridine calcium channel blockers. Class IV agents include verapamil and diltiazem. Please enter User Name.

Vaughan Williams Classification of Antidysrhythmic Drugs

Email required Address never made public. The main toxic effect of antidysrhythmic drugs involve the heart, circulation and CNS.

Class I agents block the rapid inward sodium channel, slow the rate of rise of phase 0, and so decrease the rate of depolarization. Antiarrhythmic agentsalso known as cardiac dysrhythmia medicationsare a group of pharmaceuticals that are used to suppress abnormal rhythms of the heart cardiac arrhythmiassuch as atrial fibrillationatrial flutterantidydrhythmic tachycardiaand ventricular fibrillation. Since the development of the original Vaughan Williams classification system, additional agents have been used that do drgs fit cleanly into categories I through IV.

This ddugs classifies each agent based upon its unique electrophysiologic and pharmacological properties. They are used to treat dysrhythmias, and some classes are also used in the treatment of angina and hypertension. Indications They are used to treat dysrhythmias, and some classes are also used in the treatment of angina and hypertension. Ventricular arrhythmias Prevention of paroxysmal recurrent atrial fibrillation triggered by vagal overactivity Procainamide in Wolff-Parkinson-White syndrome Increases QT interval.


The class I antiarrhythmic agents interfere with the sodium channel. Class II agents include dgugsesmololpropranololand metoprolol. Decongestants Bronchodilators Cough medicines H 1 antagonists. Antiarrhythmic drugs are used to:.

Medical Pharmacology and Therapeutics E-Book. This will aid our understanding and clinical management of cardiac arrhythmias and facilitate future therapeutic developments. By using this site, you agree to the Terms of Use and Privacy Policy. Clinical Sports Medicine Collection.

There are four classes of antidysrhytmics which each have a different mechanism of action.

Pharmacological and clinical use”. Progress in Cardiovascular Diseases. Sometimes ventricular rate is excessively high because it is being driven by atrial flutter or fibrillation. They decrease conduction through the AV nodeand shorten phase two the plateau of the cardiac action potential.

CV Pharmacology | Antiarrhythmic Drugs

Antidysrhythmic drugs work by correcting abnormal cardiac function. Class III agents include: Calcium channel blockers and beta-blockers are useful for this indication. They thus reduce the contractility of the heart, so may be inappropriate in heart failure. These materials are for educational purposes only, and are not a source of medical decision-making advice. By prolonging the effective refractory period, reentry tachycardias can often be abolished.


Home Books Anesthesiology Core Review: This page was last edited on 29 Decemberat They also have potassium channel blocking properties, and so increase action potential duration and the effective refractory period. Also noteworthy is that a few class II agents like propranolol also have a membrane stabilizing effect. Xrugs recurrence of paroxysmal supraventricular tachycardia Reduce ventricular rate in patients with atrial fibrillation.

Vaughan Williams Classification of Antidysrhythmic Drugs |

It presents the drugs on two axes, instead of one, and is presented drugz tabular form. Since conduction velocity is related to how fast the membrane depolarizes, sodium channel blockers reduce conduction velocity.

You can also find results for a single author or contributor. Abnormal automaticity is thought to occur due to reduced resting membrane potential, causing antiysrhythmic membrane to be closer to the threshold for generating an action potential.

Class I agents are divided into three groups Ia, Ib, and Ic based upon their effect on the length of the action potential.

Use this site remotely Bookmark your favorite content Track your self-assessment progress and more! Abnormal conduction is usually due to conduction block or a reentry phenomenon, with the latter being the most common cause of dysrhythmias. Please enter User Name Password Error: