Atrial fibrillation (AF) is the most common form of
arrhythmia, carrying high social costs. It is usually first seen by general practitioners or in emergency departments. Despite the availability of consensus guidelines, considerable variations exist in treatment practice, especially outside specialised cardiological settings.
Cardioversion to sinus rhythm aims to: (i) restore the atrial contribution to ventricular filling/output; (ii) regularise ventricular rate; and (iii) interrupt atrial remodelling.
Cardioversion always requires careful assessment of potential proarrhythmic and thromboembolic risks, and this translates into the need to personalise treatment decisions. Among the many clinical variables that affect strategy selection, time from onset is crucial. In selected patients, pharmacological
cardioversion of recent-onset AF can be a safely used, feasible and effective approach, even in internal medicine and emergency departments. In most cases of recent-onset AF, pharmacological
cardioversion provides an important--and probably more cost effective--alternative to
electrical cardioversion, which can then be employed as a second-line
therapy for nonresponders. Class IC agents (
flecainide or
propafenone), which can be safely used in hospitalised patients with recent-onset AF without
left ventricular dysfunction, can provide rapid conversion to sinus rhythm after either
intravenous administration or oral loading. Although intravenous
amiodarone requires longer conversion times, it is still the standard treatment for patients with
heart failure.
Ibutilide also provides good conversion rates and could be used for AF patients with
left ventricular dysfunction (were it not for high costs). For long-lasting AF most pharmacological treatments have only limited efficacy and
electrical cardioversion remains the gold standard in this setting. However, a widely used strategy involves pretreatment with
amiodarone in the weeks before planned
electrical cardioversion: this provides optimal prophylaxis and can sometimes even restore sinus rhythm.
Dofetilide may also be capable of restoring sinus rhythm in up to 25-30% of patients and can be used in patients with
heart failure. The potential risk of proarrhythmia increases the need for careful therapeutic decision making and management of pharmacological
cardioversion. The results of recent trials (AFFIRM [
Atrial Fibrillation Follow-up Investigation of Rhythm Management] and RACE [Rate Control versus
Electrical Cardioversion for
Persistent Atrial Fibrillation]) on rate versus rhythm control strategies in the long term have led to a generalised shift in interest towards rate control. Although carefully designed studies are required to better define the role of pharmacological rhythm control in specific AF settings, this alternative option remains a recommendable strategy for many patients, especially those in acute care.