Pharmacological Cardioversion of Atrial Fibrillation: Which Drugs Are Preferred, Class IC or Class III?

It is accepted that pharmacological treatment of recent-onset atrial fibrillation (AF) in order to reset sinus rhythm restoration, if effective and safe, is doubtless the favourite approach, since it is preferred by patients over electrical cardioversion. Nonetheless, it must be remembered that the placebo effect is very consistent (> 50% at 12–24 h) for AF duration of 48 h or less. Also, class I and class III antiarrhythmic drugs are not equivalent, and should be used according to their electrophysiological and pharmacokinetic properties and to their effect on cardiac inotropism, which must be strictly connected to the clinical condition of the patient. Pharmacological treatment can be carried out either intravenously or per os; and the availability of orally administered drugs has made it possible for some AF patients to treat themselves at home. There are three main factors that must be taken into consideration in choosing the appropriate drug for AF cardioversion: the duration of the arrhythmia, the clinical context in which it takes place, and the ventricular function. AF duration is also the most important factor influencing the possibility of sinus rhythm restoration. The present review discusses two types of AF: AF of less than 48-h duration and AF of more than 48-h duration. According to the guidelines of the American College of Chest Physicians, in AF of < 48-h duration, antithrombotic treatment can be avoided due to a low thromboembolic risk linked with cardioversion (< 1%) [1].