Early cardioversion no better than delayed cardioversion for recent-onset symptomatic atrial fibrillation

Reference

Pluymaekers NAHA, Dudink EAMP, Luermans JGLM, et al, for the RACE 7 ACWAS Investigators. Early or delayed cardioversion in recent-onset atrial fibrillation. N Engl J Med 2019;330(16):1499-1508.

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 ED with new or recurrent symptomatic atrial fibrillation of recent onset (< 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 pharmacological 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 ED for delayed cardioversion. The 2 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 3 patients in the delayed group and 5 in the early group required hospitalization; all others were discharged from the ED. The median duration of the index ED 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 4-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 2 groups.