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.