Background: Atrial fibrillation (Afib) is the most common arrhythmia requiring treatment in the ED. There is a paucity of literature regarding the management of acute (onset < 48 h) atrial fibrillation in this setting and no conclusive evidence exists regarding the superiority of pharmacologic vs. electrical cardioversion.
Study design: Multicenter, single-blind, randomized, placebo-controlled trial.
Setting: 11 Canadian academic medical centers.
Synopsis: In this trial of 396 patients with acute Afib, half were randomly assigned to pharmacologic cardioversion with procainamide infusion (followed by DC cardioversion, if unsuccessful), while half were given a placebo infusion then DC cardioversion. The primary outcome was conversion to sinus rhythm, with maintenance of sinus rhythm at 30 minutes. A secondary protocol evaluated the difference in efficacy between anterolateral (AL) and anteroposterior (AP) pad placement
The “drug-shock” group achieved and maintained sinus rhythm in 96% of cases, compared to 92% in the “placebo-shock” group (statistically insignificant difference). The procainamide infusion alone achieved and maintained sinus rhythm in 52% of recipients, who thereby avoided the need for procedural sedation and monitoring. Notably, only 2% of patients in the study required admission to the hospital. Pad placement was equally efficacious in the AL or AP positions. The most common adverse event observed was transient hypotension during infusion of procainamide. No strokes were observed in either arm. Follow-up ECGs obtained 14 days later showed that 95% of patients remained in sinus rhythm.
Bottom line: Pharmacologic cardioversion with procainamide infusion and/or electrical cardioversion is a safe and efficacious initial management strategy for acute atrial fibrillation, and all but eliminates the need for hospital admission.
Citation: Stiell IG et al. Electrical versus pharmacological cardioversion for emergency department patients with acute atrial fibrillation (RAFF2): a partial factorial randomized trial. Lancet. 2020 Feb 1;395(10221):339-49.
Dr. Lawson is assistant professor of medicine, section of hospital medicine, at the University of Virginia School of Medicine, Charlottesville.