Cardioversion of recent-onset atrial fibrillation: current evidence, practical considerations, and controversies in a complex clinical scenario

Atrial fibrillation (AF) represents the most common arrhythmia and is associated with increased morbidity and mortality generating high social costs. Due to its high prevalence, AF is usually managed not only by cardiologists but also by general practitioners or clinicians in emergency departments. The conventional classification of AF includes "recent-onset AF" defined as an arrhythmia episode shorter than 48 hours. In patients with a definite duration of AF of less than 24 hours and a very low-risk profile (CHA(2)DS(2)VASc of 0 in men and 1 in women), the thromboembolic risk seems to be low, and the standard 4-week anticoagulation therapy is now regarded as optional treatment. Cardioversion (electrical or pharmacological) in recent-onset AF represents a valid rhythm control strategy. Electrical cardioversion is usually reserved for hemodynamically unstable patients and performed with biphasic waveform shocks. On the other hand, pharmacological cardioversion is preferred in hemodynamically stable patients. Several antiarrhythmic drugs have been studied so far, but some questions still remain unresolved mainly due to lack of randomized clinical trials and prospective studies. The current guidelines do not uniformly agree on which drug to use for pharmacological cardioversion, and drug preference varies widely in clinical practice. The aim of this narrative review is to sum up and critically evaluate novel evidence regarding recent-onset AF as well as to provide some practical considerations particularly focused on rhythm control with pharmacological cardioversion.