Early vs. Delayed Cardioversion in Recent onset of Atrial Fibrillation

We know from prior studies that acute atrial fibrillation will frequently spontaneously revert. So, when patients arrive to the ED, which is better? Immediate cardioversion or a “wait-and-see" approach.

To attempt to answer this question, these Dutch investigators conducted a multicentre randomised noninferiority trial. They enrolled stable patients with recent onset (less than 36 hours) to early cardioversion vs. wait-and-see.

The wait-and-see approach involved giving rate control medications and eventual cardioversion if the AF was not resolved by 48 hours.  

The primary endpoint was the presence of sinus rhythm at 4 weeks. However, there were other important secondary measures they captured such as rate of spontaneous resolution, resource utilisation, recurrence of AF, safety etc.

Results?

By 4 weeks both groups were about the same and within their prespecified non-inferiority margin. Sinus rhythm was present in 91% of the delayed group vs. 94%.

So, it doesn’t matter?

Perhaps it does… In the delayed group, the rate of spontaneous resolution was 70%! This begs the question, why do we bother with such an early aggressive approach to AF when it very often spontaneously resolves.  Can we limit the potential harms of antiarrhythmic medications and procedural sedations and let nature take its course?

These findings are consistent with prior research… Doyle B et al. Heck, I may not ever get published in the NEJM but at least I have been referenced! 

What do I do?

This is the time for shared decision making. Pull up a chair and have a chat to the patient.  It also depends on how symptomatic the patient is, their prior experiences, rates of recurrence, and dare I say, a busy department.

Quick… don’t just do something, stand there!

Covering:

Pluymaekers N, Crazy Dutch Name, Dudink J, Luermans J, et al. Early or Delayed Cardioversion in Recent-Onset of Atrial Fibrillation. N Engl J Med 2019;380:1499-1508. [link to article]