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Metoprolol vs. Diltiazem for Rate Control in Atrial Fibrillation
Quick Takes
- Metoprolol and diltiazem demonstrated similar efficacy in controlling ventricular rate in patients with atrial fibrillation.
- Adverse events were rare and occurred at similar rates between patients treated with metoprolol and diltiazem.
Study Questions:
Is metoprolol or diltiazem better at controlling ventricular rate in patients with atrial fibrillation?
Methods:
This single-center, retrospective cohort study was conducted between 2015 and 2019. Eligible patients presented to the emergency department with electrocardiogram-confirmed atrial fibrillation with rapid ventricular rate (heart rate >120 bpm) and received either metoprolol or diltiazem for treatment. The primary outcome was percentage of patients who achieved heart rate <100 bpm within 2 hours of medication administration. Secondary outcomes included time to rate control, percentage of patients requiring additional medications, and incidence of cardioversion, bradycardia (heart rate <60 bpm), and hypotension (systolic blood pressure <90 mm Hg requiring vasopressors).
Results:
A total of 200 patients, 100 per arm, were included in the study. Significantly more patients who were treated with diltiazem were not taking any rate-controlling medications prior to admission (37% vs. 10%, p < 0.001). Rate control was achieved in 35% and 41% of the metoprolol and diltiazem groups, respectively (p = 0.38). There were no significant differences in the number of doses required to achieve rate control between groups. Mean time to achieve rate control was also not statistically different among patients receiving metoprolol or diltiazem (35 vs. 21 minutes, p = 0.23). Adverse events were rare and not significantly different between groups, with one patient experiencing hypotension (metoprolol) and four requiring cardioversion (one metoprolol, three diltiazem). No patients experienced bradycardia.
Conclusions:
This study demonstrates no significant difference in achievement of rate control in patients with atrial fibrillation treated with either metoprolol or diltiazem. No between-group differences were identified that would suggest benefit or harm with one agent compared to the other for acute rate control with atrial fibrillation.
Perspective:
This study represents the largest study to date comparing these two drug classes for acute rate control in patients with atrial fibrillation. Although the study is a retrospective evaluation of a relatively small sample, the results support current practice guidelines, which do not recommend use of one agent over the other for this indication.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias
Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Fibrillation, Blood Pressure, Bradycardia, Diltiazem, Electric Countershock, Electrocardiography, Emergency Service, Hospital, Heart Rate, Hypotension, Metoprolol, Patient Care Team, Secondary Prevention, Treatment Outcome
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