176: DILTIAZEM VERSUS METOPROLOL FOR ATRIAL FIBRILLATION WITH RAPID VENTRICULAR RATE IN THE ED

Abstract

Introduction: Atrial fibrillation (AF) is the most prevalent persistent cardiac arrhythmia observed in clinical practice and the most common dysrhythmia treated by EM physicians. Due to the side effect profile of the two pharmacotherapeutic treatment methods (rate vs rhythm), rate control is considered the primary approach in most patients. According to the 2014 AHA/ACC/HRS guideline for patients with AF, both beta-blockers and non-dihydropyridine calcium channel blockers are recommended with the same level of evidence. Methods: This was a retrospective chart review of patients who came into the ED with AF with RVR. Patients included were administered oral diltiazem, IV diltiazem, and/or IV metoprolol for HR control. If patients didn’t meet any exclusion criteria, they were randomized to the study groups 1:2:2. The primary outcome measured was the percentage of patients with heart rate (HR) < 110 bpm within two hours post medication administration. Secondary outcomes included percentage of patients with HR < 110 bpm in four hours post medication administration, HR at 5 minutes, 15 minutes, 30 minutes, 1 hour, and 2 hours post medication administration, number of doses needed to achieve HR < 110 bmp, need for continuous rate control infusion, and need for administration of antiarrhythmic medications. Safety was assessed through the incidence of SBP < 90 and HR < 60. Kruskal-Wallis Test was performed to compare clinical endpoints. An alpha value of ≤ 0.05 was considered statistically significant. Results: Eighty-five patients were included in the study analysis. The primary outcome didn’t differ between the groups (56.3% oral diltiazem, 36.5% IV diltiazem and 46.1% IV metoprolol, p= 0.27, H statistic 2.613). The secondary outcome of percentage of patients with heart rate < 110 bpm four hours post medication administration did not differ between the groups (63.9% oral diltiazem, 48% IV metoprolol and 36.5% IV diltiazem, p= 0.074, H statistic 5.2026). There was a total of 14 times safety outcomes were experienced between the three groups. Conclusions: There was no difference between treatment groups in the percentage of patients with heart rate < 110 bpm two hours post medication administration. Further studies are needed to evaluate oral diltiazem in this setting compared to intravenous rate control therapy.