Comparison of sustained rate control in atrial fibrillation with rapid ventricular rate: Metoprolol vs. Diltiazem

The objective of this study was to compare sustained rate control with intravenous (IV) diltiazem vs. IV metoprolol in acute treatment of atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED).

This retrospective chart review at a large, academic medical center identified patients with AF with RVR diagnosis who received IV diltiazem or IV metoprolol in the ED. The primary outcome was sustained rate control defined as heart rate (HR) < 100 beats per minute without need for rescue IV medication for 3 h following initial rate control attainment. Secondary outcomes included time to initial rate control, HR at initial control and 3 h, time to oral dose, admission rates, and safety outcomes.

Between January 1, 2016 and November 1, 2018, 51 patients met inclusion criteria (diltiazem n = 32, metoprolol n = 19). No difference in sustained rate control was found (diltiazem 87.5% vs. metoprolol 78.9%, p = 0.45). Time to rate control was significantly shorter with diltiazem compared to metoprolol (15 min vs. 30 min, respectively, p = 0.04). Neither hypotension nor bradycardia were significantly different between groups.

Choice of rate control agent for acute management of AF with RVR did not significantly influence sustained rate control success. Safety outcomes did not differ between treatment groups.