(179) Evaluation of Diltiazem Dosing Strategies in Atrial Fibrillation With Rapid Ventricular Response

Introduction: Atrial fibrillation (AF) with rapid ventricular response (RVR) is a common tachyarrhythmia that results in over 500,000 emergency department (ED) visits in the United States per year. Current guidelines recommend the use of non-dihydropyridine (DHP) calcium channel blockers (CCB) for AF RVR. Diltiazem is a frequently used non-DHP in the ED for rate control and is available in a variety of formulations, though most often as a continuous intravenous infusion (CIVI). The use of CIVI diltiazem may require intensive care unit admissions and more frequent monitoring, which can cause a significant burden on the health care system. The purpose of our study is to compare the incidence of treatment failure between oral immediate release and CIVI diltiazem following an initial IV loading dose in patients in AF with RVR.

Methods: This institutional review board-approved, single center, retrospective cohort study was conducted at a large, community teaching emergency department in Dallas, Texas. Adults that presented to the emergency department from July 1, 2022, to June 30, 2022, who received diltiazem IV bolus were included in the preliminary screening. Patients were placed into their respective groups based on the receipt of oral or CIVI diltiazem after the initial bolus. Patients were excluded if they demonstrated hemodynamic instability prior to drug therapy intervention, if they had administration of any rate-controlling medication, anti-arrhythmic medication, or direct current cardioversion prior to the initial diltiazem IV bolus.

Results: Of the 776 patients screened, 171 patients met criteria for inclusion. At baseline, the average age was 67 years, 73% were male and 93% were Caucasian. There was no significant difference in the rate of treatment failure between the PO and CIVI groups (60% vs 59%, p=0.93), the PO group had a higher incidence of requiring additional boluses (31% vs 9.3% p< 0.001), whereas, the CIVI had more heart rates above 110 bpm (27% vs 45%, p=0.013) at 4 hours. There was no significant difference in the rate of clinically significant hypotension (11.7% vs 8.1% p=0.428).

Conclusions: Based on this retrospective review, initiating oral diltiazem, after an initial IV bolus, does not result in more treatment failures for AF with RVR than initiating a continuous infusion.