A comparison of diltiazem versus metoprolol for patients with atrial fibrillation presenting to the emergency department with rapid ventricular rate

<h2>Abstract</h2><h3>Background</h3> Atrial fibrillation (AF) is one of the most common cardiac dysrhythmias and one of the most commonly encountered dysrhythmias in emergency departments (EDs). Rate control is vital to relieve symptoms and prevent complications in patients who present with AF and a rapid ventricular rate (RVR), defined as a heart rate (HR) > 120 beats per minute (bpm). Both metoprolol and diltiazem are recommended for the management of RVR in AF; however, the comparative effectiveness of these medications is unclear. <h3>Objectives</h3> The primary objective of this quality improvement project was to evaluate the achievement of rate control, defined as a HR < 110 bpm or an HR reduction > 20%, within 30 minutes of the first dose of IV diltiazem or metoprolol. The secondary objectives were rate control within 60 minutes of the first dose, rate control within 180 minutes of the first dose, occurrence of repeat dosing, additional medications required for rate control, worsening heart failure (HF) symptoms, admission and discharge diagnoses, hospital readmission within 7 days of discharge, and length of hospital stay. We also assessed the incidence of hypotensive and bradycardic events within 60 minutes of the first dose. <h3>Methods</h3> A total of 571 patient charts were screened for inclusion in this quality improvement project and 151 patients were included. <h3>Results</h3> In a multivariate logistic regression model, with controls for patient age, rate control within 180 minutes of the first dose, and repeat dosing of medication given, there was no statistically significant difference in the primary outcome of rate control within 30 minutes between IV diltiazem (77%) and metoprolol (65%) (odds ratio 0.56 [95% CI 0.22-1.39], <i>P</i> = 0.27). We also found no statistically significant differences in the multivariate models for the incidence of worsening HF, hypotension, or bradycardia. Minimal adverse effects were observed. <h3>Conclusions</h3> The results of this study expand upon previous literature that suggested that diltiazem is likely to be safe and effective in the acute management of AF with RVR, given that there was no statistically significant difference between the 2 study drugs in the achievement of rate control or documentation of worsening HF.