Christina Tran, BCCCP, PharmD, RPh
Clinical Pharmacy Specialist
VA North Texas Health Care System
Dallas, Texas
Disclosure information not submitted.
Title: Emergency Room Diltiazem Dose Evaluation in Atrial Fibrillation/Flutter with Rapid Ventricular Rate
Introduction: Patients present to emergency department (ED) with atrial fibrillation/flutter (AF) with rapid ventricular response (RVR) necessitating rate control. Initially, due to perceived risks, lower doses than guideline recommended intravenous (IV) diltiazem boluses may be given. We to evaluate the efficacy and safety of low-dose diltiazem (< /=0.2 mg/kg) compared to guideline dosing ( >0.2 mg/kg) for AF with RVR.
Methods: Electronic medical records of patients who presented to the VA North Texas Health Care System (VANHTCS) ED between December 2018 to May 2020 with AF with RVR who received IV diltiazem as initial rate control agent were reviewed. Patients with excluded if cardioversion or emergent therapy was required prior to IV diltiazem, missing data, hemodynamic instability (SBP < 90 mmHg or requiring vasopressor/inotrope support). Primary efficacy outcome defined as reduction of lowest ventricular response rate (VRR)< /= 100 bpm or reduction of VRR >/=20% from baseline while in the ED. Secondary outcomes included additional IV rate control agent given in ED and a composite safety outcome defined as: lowest SBP < 90 mmHg, reduction of SBP >/=20% or greater from baseline, respiratory failure requiring intubation, cardiac arrest, or new onset of unstable dysrhythmias requiring emergency interventions.
Results: Among 91 included patients (mean age, 68.4 years; 96.7% men; mean BMI 30.8), 67 and 24 were included in low and guideline dose cohorts respectively. There was no significant difference in primary efficacy outcome (39 [58.2%] low dose vs. 17 [70.8%] standard dose; p=0.275). Composite safety outcome occurred in (18 [26.9%] low dose vs. 9 [37.5%] guideline dose, p=0.328). 38 (56.7%) low dose cohort vs. 11 (45.8%) guideline dose cohort required additional IV rate control agent while in ED (p=0.437).
Conclusions: Among patients presenting to VA ED with AF with RVR, low dose and guideline dose diltiazem did not appear to differ for any outcomes. There was a trend towards higher composite primary efficacy outcome and composite safety outcome rates in those that received guideline recommended dose. These findings did not appear to support initial diltiazem dose as recommended by guidelines for this older, predominantly male population. Future large, prospective randomized controlled trials are needed.