Antiarrhythmic Drugs Classification Chart
The Antiarrhythmic Drug List (ADL) is a list of medications used to treat or prevent heart rhythm disorders such as atrial fibrillation (AF), ventricular tachycardia (VT), and atrioventricular conduction block (AVCC). These medications are classified into three groups: 1) Class I – Class IIa – Class IIIb.
Classes I through IV are considered to have no proven benefit over placebo in terms of improving survival or quality of life. However, there is some evidence that they may reduce the risk of death from cardiovascular causes. There is no evidence that any class I or IIa medication reduces the risk of sudden cardiac arrest (SCA).
There is good evidence that classes III and IV do not increase the risk of SCA; however, there is limited data on their effectiveness in reducing mortality. Classes III and IV are generally prescribed only when other treatments have failed.
Classes V and VI are considered to be the most effective classes of medications. They appear to offer the greatest improvement in survival, decrease the risk of SCA, and reduce all cause mortality.
Classes VII through X are considered ineffective for treating or preventing cardiovascular disease. Although there is some evidence that these classes may lower blood pressure, there is little evidence on their effectiveness in decreasing mortality from cardiovascular causes.
Listed below are the classes of antiarrhythmic drugs, followed by a description of each drug class and examples of specific drugs within each class. For an in-depth description of each class, including warnings, adverse effects, and dosage information, click on the link for the class name.
Class I antiarrhythmics work by prolonging the duration of the action potential and refractory period.
Class II antiarrhythmics work by blocking sodium channels. They are often used to treat atrial fibrillation.
Class III antiarrhythmics work by blocking the potassium channels. They are often used to treat ventricular tachycardia.
Class IV antiarrhythmics work by blocking the calcium channels. They are often used to treat ventricular tachycardia and atrial fibrillation.
Class V antiarrhythmics work by affecting the sodium-potassium pump. They are often used to treat atrial fibrillation and supraventricular tachycardia.
Class VI antiarrhythmics work by prolonging the action potential and refractory period. They are useful in treating atrial fibrillation, although they can cause significant side effects.
Class VII antiarrhythmics work by affecting sodium and potassium. They are often used to treat ventricular tachycardia but may also be given following a heart attack.
Class VIII antiarrhythmics are not available in the United States. They work by decreasing intracellular calcium. They are useful in treating atrial fibrillation, although they can cause serious side effects.
Sources & references used in this article:
Long-term survival of patients with malignant ventricular arrhythmia treated with antiarrhythmic drugs by TB Graboys, B Lown, PJ Podrid, R DeSilva – The American journal of …, 1982 – Elsevier
Aggravation of arrhythmia by antiarrhythmic drugs—incidence and predictors by PJ Podrid, S Lampert, TB Graboys, CM Blatt… – The American journal of …, 1987 – Elsevier
hERG potassium channels and cardiac arrhythmia by MC Sanguinetti, M Tristani-Firouzi – Nature, 2006 – nature.com
Can antiarrhythmic drugs cause arrhythmia? by PJ PODRID – The Journal of Clinical Pharmacology, 1984 – Wiley Online Library
Use of nonsustained ventricular tachycardia as a guide to antiarrhythmic drug therapy in patients with malignant ventricular arrhythmia by PJ Podrid, A Schoeneberger, B Lown, S Lampert… – American heart …, 1983 – Elsevier
Clinical predictors of arrhythmia worsening by antiarrhythmic drugs by W Slater, S Lampert, PJ Podrid, B Lown – The American journal of …, 1988 – Elsevier
Aggravation of arrhythmia induced with antiarrhythmic drugs during electrophysiologic testing by RF Poser, PJ Podrid, F Lombardi, B Lown – American heart journal, 1985 – Elsevier
Zebrafish embryos express an orthologue of HERG and are sensitive toward a range of QT-prolonging drugs inducing severe arrhythmia☆ by U Langheinrich, G Vacun, T Wagner – Toxicology and applied …, 2003 – Elsevier