From a recent paper:
We enrolled consecutive patients presenting to our community hospital with recent onset AF into a protocol, which called for rhythm control with procainamide and if unsuccessful electrical cardioversion and discharge home. We compared this prospective cohort with matched historical controls. Primary outcome was admission rate. We also compared ED conversion rates and lengths of stay (LOS). We reported 30-day data on the study group including ED recidivism, recurrent AF, outpatient follow-up, and any important adverse events.
Fifty-four patients were enrolled in the study group with 4 being admitted compared with 30 of 50 in the historical control group. Ninety-four percent of the study group converted compared with 28% in the historical control. Both hospital and ED LOS were significantly shorter for the study group. Six patients had recurrent AF, and 4 of those returned to the ED.
The patient had to have had onset of atrial fibrillation within 48 hours. In patients without cardiac awareness this would be difficult to determine. If there was any doubt on the part of the treating physician the patient was excluded.
This makes it look so nice and easy but I think anticoagulation should enter the discussion. There are two aspects of anticoagulation to consider: prior to conversion (either immediately pre-prodedure or for a month or so prior) and after conversion, for a month or more, due to the thromboembolic risk resulting from atrial stunning post conversion, as well as the possibility that AF will recur. For people who have been in AF for less than 48 hours the widespread belief (and the tacit assumption in this article) is that you don't need to worry about it. The patients in this study, apparently, were not anticoagulated, given that the body of the paper states that no new medications were prescribed at ER discharge. However, the question deserves more nuance than it is usually given. There is actually some controversy around the decision not to anticoagulate in cases of AF of less than 48 hours duration. The evidence to guide clinicians is not the greatest. The guideline statement is very vague (one can consider anticoagulation, before and/or after, or not) and is in the form of a IIb recommendation. The condition for that statement is that the patient be deemed low risk. Up to Date expresses concern about this no anticoagulation approach and suggests it only for patients at very high bleeding risk or those who are CHADS VASC zero. Some of their experts recommend anticoagulation before and/or after (for a month) even for those low risk patients. This is an under-discussed elephant in the room.