Which medications in the drug class Antiarrhythmics, class IA are used in the treatment of Atrial Fibrillation?

Updated: Nov 18, 2019
  • Author: Lawrence Rosenthal, MD, PhD, FACC, FHRS; Chief Editor: Jeffrey N Rottman, MD  more...
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Antiarrhythmics, class IA

Quinidine, procainamide, and disopyramide are class IA antiarrhythmic agents used to maintain sinus rhythm. Generally, start administration in the hospital because of the high risk of adverse effects. All patients treated with class IA agents should be treated concomitantly with AV nodal blocking agents. Some patients demonstrate a slowing in the atrial rate and an increase in AV conduction, with rapid ventricular rates, when treated with class IA agents alone. They are fading as first-line drugs for AF.

Quinidine (Cardioquin, Quinalan, Quinidex, Quinaglute)

Of Vaughn-Williams class IA agents, only quinidine is FDA approved for atrial fibrillation. As with all class IA agents, QRS and QTc prolongation are the main ECG manifestations. It should not be used in patients with a prolonged QTc baseline (>460 milliseconds). Quinidine has generally fallen out of favor as a first- or second-line agent for the treatment of atrial fibrillation.

Procainamide (Procanbid, Pronestyl)

Procainamide is not FDA approved for the treatment of atrial fibrillation; however, many use this agent for acute cardioversion (eg, postoperatively) and because it can be administered intravenously. Intravenous administration is useful for acute conversion, and it can subsequently be converted to an oral dose. It is a negative inotropic agent and vasodilator, and care must be taken when administering to patients with reduced LV function. It is generally considered a second-line agent.

Disopyramide (Norpace)

Disopyramide is not commonly used to treat atrial fibrillation because it has adverse anticholinergic effects and because it is a strongly negative inotropic agent, which may precipitate CHF and cardiogenic shock in patients with reduced LV function. It may be useful in vagally mediated syncope.

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