108 Skip the Drip: Oral Diltiazem for Rate Control in Rapid Atrial Fibrillation

Diltiazem is a frequent pharmacological treatment for atrial fibrillation (AF) with rapid ventricular response (RVR) in the ED. The most common dosing is an intravenous (IV) bolus followed by a continuous infusion. An IV bolus followed by oral diltiazem might reduce treatment cost and adverse events. The primary study objective was to test the safety and efficacy this IV then oral approach compared to a bolus and infusion approach. This was a multicenter, retrospective cohort study. The setting was 6 academic and community EDs. We included patients who received oral or continuous infusion of diltiazem following an initial IV loading dose for treatment of AF with RVR. We excluded patients with a presenting pulse rate < 120 beats/min and those who received other concomitant antiarrhythmic drugs. The primary outcome was assessed by need for additional IV boluses of rate control medications for rescue therapy. Secondary outcomes included administration of vasopressors for treatment associated hypotension and hospital length-of-stay. Over a 30-month period, there were 1867 eligible patients. There were 1651 in the bolus + infusion group and 216 in the bolus + oral diltiazem group. New-onset AF was present in 31.8%. Rescue medications were required for rate control in 24.5% of patients, and 3.4% required a vasopressor for treatment associated hypotension. The rate of rescue treatment for rate control was not significantly different between the oral diltiazem (27.8%) and infusion (24.1%) groups (OR 1.2, 95% CI 0.9 - 1.7). Patients with new-onset AF were more likely to require rescue therapy (OR 1.4, 95% CI 1.1 - 1.7). There was a significantly higher rate of vasopressor treatment in the infusion (3.7%) compared to the oral diltiazem cohort (0.9%), OR 4.1 (95% CI 1.0 - 16.9). Patients who required rescue therapy had double the rate of vasopressor treatment for diltiazem-associated hypotension (OR 1.9, 95% CI 1.2 - 3.3). Finally, the hospital length of stay was shorter for patients in the oral diltiazem group (6 days) compared to the infusion group (7.2 days, difference 1.2, 95% CI -0.2 to 2.6 days). In the treatment of AF with RVR in the ED, these results indicate that oral diltiazem has similar efficacy and fewer treatment related adverse vents compared to a diltiazem infusion. Prospective trials are indicated to test these strategies in select patients.