Clinical Question

Is it necessary to immediately restore sinus rhythm by early cardioversion in patients who present to the emergency department with recent-onset symptomatic atrial fibrillation?

Bottom Line

For patients presenting to the emergency department with recent-onset symptomatic atrial fibrillation, early cardioversion is no better than delayed cardioversion in achieving sinus rhythm within four weeks. The delayed approach results in more spontaneous conversions to sinus rhythm, avoiding cardioversion altogether, without increasing the rate of cardiovascular complications. (Level of Evidence = 1b)

Synopsis

Atrial fibrillation can often terminate spontaneously without the need for pharmacologic or electrical cardioversion. In this study, investigators included adults who presented to the emergency department with new or recurrent symptomatic atrial fibrillation of recent onset (less than 36 hours). The patients were randomized into a delayed cardioversion group (n = 218) or a standard early cardioversion group (n = 219). In the early group, patients received immediate pharmacologic cardioversion with flecainide (or electrical cardioversion if flecainide was contraindicated or unsuccessful) and were discharged when stable. In the delayed group, patients received rate-controlling medications, were discharged when clinically stable, and were given outpatient follow-up the next day. If they remained in atrial fibrillation, they were then referred back to the emergency department for delayed cardioversion. The two groups were balanced at baseline: mean age was 65 years, approximately 40% were taking anticoagulants, and two-thirds had a CHA₂DS₂-VASc score of 2 or higher. Only three patients in the delayed group and five in the early group required hospitalization; all others were discharged from the emergency department. The median duration of the index emergency department visit was 158 minutes in the early group and 120 minutes in the delayed group. The primary outcome of the presence of sinus rhythm on an electrocardiogram at a four-week outpatient visit occurred in 91% of the delayed group and 94% of the early group, meeting noninferiority criteria for the delayed approach (P = .005). In the delayed group, 69% converted to sinus rhythm spontaneously within 48 hours after rate-control medication and only 28% required delayed cardioversion. The number of cardiovascular complications were infrequent and did not differ between the two groups.

Study design: Randomized controlled trial (nonblinded)

Funding source: Government

Allocation: Concealed

Setting: Emergency department

Reference: Pluymaekers NA, Dudink EA, Luermans JG, et al.; RACE 7 ACWAS Investigators. Early or delayed cardioversion in recent-onset atrial fibrillation. N Engl J Med. 2019;380(16):1499–1508.