Safety of Three Intravenous Rate-Reducing Regimens for Atrial Fibrillation With Rapid Ventricular Response

Atrial fibrillation (AF) with rapid ventricular response (RVR) is commonly encountered in the emergency department (ED) and treated with intravenous (IV) beta blocker (BB) or calcium channel blocker (CCB) therapy. Guidelines advise against combining these IV medications due to concerns for hypotension and bradycardia. No studies have compared dual IV BB and CCB therapy with monotherapy. We sought to evaluate the safety of this combination compared with monotherapy.

We conducted a data-only retrospective cohort study across 21 community EDs. We included adult patients who presented with primary AF (not secondary to another cause) and heart rate greater than 110 beats/minute followed by 1 of 3 treatments: BB alone, CCB alone, or both (in either order separated by <4h). Primary outcomes were hypotension (systolic blood pressure < 90mmHg), bradycardia (heart rate < 50 beats/minute), and IV vasoactive medications. We performed a survival analysis over a 4-hour time period starting with the initial IV BB or CCB bolus with censoring by cardioversion initiation, patient leaving the hospital, death, or end of follow-up. We report unadjusted Cox proportional hazard ratios (HRs).

We identified 103,816 potentially eligible patient encounters and included 42,903 in our analysis after applying exclusion criteria such as no primary AF, RVR, or IV BB or CCB medications. Mean age was 69.5 years (SD 13.6) and 52% of patients were female. For treatment, 14,669 (34.2%) received IV BB only, 23,764 (55.4%) received IV CCB only, and 4,470 (10.4%) received both. There were 3,638 cases of hypotension, 404 cases of bradycardia, and 13 cases needing vasopressors. Compared with monotherapy, dual therapy had a higher rate of hypotension (HR 1.31; 95% CI 1.18-1.46), but not bradycardia (HR 1.14; 95% CI 0.83-1.57) or IV vasoactive medications (HR 3.87; 95% CI 0.67-22.4).

We found that the use of combined IV BB and CCB for AF RVR was associated with a greater rate of hypotension, but not bradycardia or vasopressor medication use. On further analysis, we will identify associated risk factors. Prospective studies are needed to further evaluate safety outcomes.