Esther Asiamah, PharmD; Laura Zizza, PharmD, BCCP; Michael Perza, PharmD, BCPS, BCEMP; Alexandra Novinger, PharmD; Brandi Steady, PharmD, BCCP; Regina Ianni, PharmD, BCPS
Objective: The objective of this study is to compare the safety and short-term outcomes of intravenous (IV) metoprolol and IV diltiazem for rate control in this population
Self-Assessment Question: Which concern limits guideline use of diltiazem in patients with heart failure with reduced ejection fraction?
A. QT prolongation
B. Negative inotropic effects
C. Increased renal clearance
D. Reduced beta receptor sensitivity
Background: Atrial fibrillation (AF) with rapid ventricular response in heart failure with reduced ejection fraction (HFrEF) is commonly managed with beta blockers, while diltiazem is generally avoided due to negative inotropic effects
Methods: This retrospective cohort study included adults presenting to the ED from January 2020 to June 2025 with AF with rapid ventricular response and ejection fraction <40% who received IV metoprolol or IV diltiazem. The primary outcome was clinical deterioration within 48 hours, defined as escalation of respiratory support, vasopressor or inotrope use, or intensive care unit (ICU) transfer. Secondary outcomes included safety events (bradycardia, hypotension, emergent cardioversion within 120 minutes) and efficacy, defined as achievement of heart rate <100 bpm at 30, 60, or 120 minutes. Disposition outcomes included ICU admission, ED readmission for heart failure, and ED discharge within 48 hours
Results: A total of 580 patients were screened, of whom 46 met inclusion criteria (metoprolol n=30; diltiazem n=16). There was no difference in the primary outcome; 1 patient (6.3%) in the diltiazem group required escalation of respiratory support, with no vasopressor use, inotropes, or ICU transfers. There were no statistically significant differences in secondary outcomes, including safety, efficacy, and disposition between the groups. Safety events were observed only in the metoprolol group, including emergent cardioversion (n=9) and adverse events (n=3; hypotension n=1, bradycardia n=2), with none in the diltiazem group. Rate control, defined as HR <100 bpm was achieved in 4 patients (13.3%) receiving metoprolol and 7 (43.8%) receiving diltiazem. Most patients were discharged (metoprolol n=29, 96.7%; diltiazem n=13, 81.3%
Conclusion: Intravenous diltiazem demonstrated similar safety and short-term outcomes compared with intravenous metoprolol in patients with HFrEF presenting with atrial fibrillation with rapid ventricular response, with no difference in clinical deterioration. This study was underpowered, and larger studies are needed to further evaluate the safety and effectiveness of diltiazem in this population.
