Intravenous diltiazem infusions for rapid atrial fibrillation or flutter in the emergency department: A retrospective, exploratory analysis

Background: Emergency physicians commonly treat patients with atrial fibrillation (AF) or atrial flutter (AFL) with rapid ventricular response, and intravenous (IV) diltiazem is the most commonly used medication for rate control of such patients. We sought to compare rate control success and safety outcomes for emergency department (ED) patients with AF or AFL who, after a diltiazem bolus, received a diltiazem drip compared to those who did not receive a drip. Methods: We performed a retrospective cohort study comparing outcomes of ED patients from a single hospital system with AF and AFL and a heart rate (HR) > 100 beats/min who received a diltiazem drip after an IV diltiazem bolus to those who received no drip. The primary outcome was a HR < 100 beats/min at the time of ED disposition. Secondary outcomes were hospital length of stay and safety (hypotension, electrical cardioversion, vasopressor use, and death). We compared groups using propensity score matching. Results: Between January 1, 2020, and November 8, 2022, there were 746 AF or AFL patients eligible for analysis. Of those, 382 (51.2%) received a diltiazem drip and 364 (48.8%) did not. In the unadjusted analysis, the last recorded ED HR was <100 beats/min in 55.2% of patients in the drip group compared to 65.9% in the no-drip group (difference 10.7%, 95% confidence interval [CI] 3.7 to 17.7). After propensity matching, diltiazem drip use was associated with lower likelihood of rate control in the ED (OR 0.69, 95% CI 0.48–0.99) and 22.5 h (95% CI 12.2–36.8) longer hospital stay. Conclusions: For patients with AF or AFL, the use of a diltiazem drip after an IV diltiazem bolus was associated with less rate control in the ED.