A wait-and-see approach is noninferior to early cardioversion for achieving a return to sinus rhythm at 4 weeks for people seen in the emergency department with recent-onset symptomatic atrial fibrillation, according to results published in the New England Journal of Medicine.

This multicenter, open-label, noninferiority trial (ClinicalTrials.gov identifier: NCT02248753) included participants seen in the emergency department with hemodynamically stable, recent-onset (<36 hours) symptomatic atrial fibrillation. Participants were randomly assigned to be treated with a wait-and-see approach (delayed-cardioversion group; n=212) or early cardioversion (n=215). Participants in the delayed-cardioversion group were initially treated with rate-control medication only, undergoing delayed cardioversion if the atrial fibrillation did not resolve within 48 hours.

The primary end point was the presence of sinus rhythm at 4 weeks. The researchers defined noninferiority as the lower limit of the 95% CI for the between-group difference in the primary end point in percentage points was more than -10.

At 4 weeks, 91% (193/212) of participants in the delayed-cardioversion group had sinus rhythm compared with 94% (202/215) of those in the early-cardioversion group (between-group difference, -2.9 percentage points; 95% CI, -8.2 to 2.2; P =.005 for noninferiority).

Among participants in the delayed-cardioversion group, 69% (n=150) experienced spontaneous conversion to sinus rhythm within 48 hours, and another 28% (n=61) achieved sinus rhythm after delayed cardioversion. Among participants in the early-cardioversion group, 16% (n=36) experienced spontaneous conversion to sinus rhythm before cardioversion, and 78% (n=171) achieved sinus rhythm after cardioversion.

Among participants who completed remote monitoring during 4 weeks of follow-up, the researchers detected a recurrence of atrial fibrillation in 30% (49/164) of those in the delayed-cardioversion group compared with 29% (50/171) of those in the early-cardioversion group.

“Spontaneous conversion frequently occurred in patients in the delayed-cardioversion group and reduced the need for immediate pharmacologic or electrical cardioversion,” wrote the researchers.

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Disclosure: Marco Alings, MD, PhD, reports receiving advisory board fees from Bayer, Bristol-Myers Squibb, Daiichi Sankyo, Boehringer Ingelheim, and Milestone Pharmaceuticals; lecture fees from Pfizer; and grant support from Sanofi.

Reference

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