Intravenous Vernakalant for Acute Termination of Recent Onset Atrial Fibrillation in the Emergency Department

Background: Atrial fibrillation (AF) significantly heightens cardiovascular risks, especially in the first year following diagnosis. Early conversion to sinus rhythm is crucial, and while electrical cardioversion is effective, it carries sedation-related risks. Vernakalant, an atrial-selective antiarrhythmic drug, has shown potential for rapid AF termination.

Purpose: This study evaluated predictors of successful cardioversion using Vernakalant in a large cohort of emergency department (ED) patients.

Methods: We conducted a retrospective cohort study of consecutive patients presenting with recent onset AF to the ED from 2016 to 2024. Eligible patients received intravenous Vernakalant following two dosing protocols: from 2016-2022, a fixed dose of 300 mg (initial) and 200 mg (second) were infused over 10 minutes each; from 2022 onward, a weight-adjusted protocol (3 mg/kg for the first dose and 2 mg/kg for the second, up to 300 mg) was utilized. The primary efficacy outcome was conversion to sinus rhythm post-Vernakalant, while the primary safety outcome was the occurrence of severe adverse events (SAE) after treatment.

Results: Among 328 patients treated with Vernakalant, 214 (65%) received the simplified dose regimen and 114 (35%) received the weight-adjusted regimen. 268 (82%) converted to sinus rhythm. The efficacy was similar between a fixed-dose protocol and a weight-adjusted regimen, though the fixed-dose group had a higher initial conversion rate (70% vs. 56%, p=0.015). Multivariate analysis identified higher first-dose Vernakalant (adjusted OR 1.87 per additional mg/kg, p<0.01) as a significant predictor of successful cardioversion. Adverse events occurred in 10% of patients, with 0.6% experiencing SAEs. One mortality, in the weight-adjusted regimen was linked to undiagnosed dilated cardiomyopathy, highlighting the need for careful patient assessment.

Conclusion: This study supports Vernakalant`s efficacy for rapid cardioversion in the ED, demonstrating high success rates and manageable safety profiles. Increased dosing correlates with improved outcomes, indicating its clinical utility despite existing regulatory challenges.