Monday, 13 July 2020

Electrical vs pharmacological cardioversion for ED patients with acute atrial fibrillation

This was in fact two RCT’s.

The primary one was comparing conversion to sinus rhythm between a drug-before-shock strategy vs. shock only for cardioversion of acute (<48 hours) atrial fibrillation. The second was a nested RCT comparing anterioposterior vs. anterolateral pad placement.

They enrolled about 400 patients. Half were randomised to procainamide infusion before an attempt at DC cardioversion. The other half got matching placebo followed by DC cardioversion.

Both strategies were highly effective in conversion to sinus rhythm at 96% with drug/shock vs. 92% for shock only (95%CI 0-9; p=0.07). Pad placement didn’t matter.

Of note, the procainamide worked for half of the patients and they were able avoid electricity and procedural sedation.

But not emphasized in the paper was the success of doing nothing. Many patients self-reverted during their ED stay and even with placebo infusion. Perhaps we should adopt a wait-and-see approach as suggested by the Dutch and Doyle?

There are a few things to note.

They reported no adverse events at follow up. (But there was one case of “cardiac arrest” when they forgot to hit the sync button… woops!) As per prior similar studies, it looks safe.

The cohort was a bit younger (mean age 60) and most had AF for less than 12 hours. Therefore, care should be taken when extrapolating this study to older patients with longer duration of AF.

11% of patients returned to the ED with recurrent AF within 14 days. This very likely underrepresents the amount of recurrence. Which begs the question of why bother…

There was a trend towards efficacy with the drug shock group with NNT of 25 for more successful overall conversion. This makes physiological sense.

Of course, the biggest issue is procainamide is not officially available in Australia and in some other countries. The authors suggest other antiarrhythmics might be useful.

Overall, I think this is compelling evidence to a consider a drug/shock strategy. But I still think doing nothing might be even better. Time for shared decision making.



Steill I, Sivlotti M, Taljaard M, et al. Electrical vs pharmacological cardioversion for emergency department patients with acute atrial fibrillation (RAFF2): a partial factorial RCT. Lancet 2020;395:339-49. [link to article]

SGEM#260: Quit Playing Game with My Heart – Early or Delayed ...

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