Compare heart rate control between parenteral metoprolol and diltiazem and identify safety outcomes in the acute management of atrial fibrillation (AFib) with rapid ventricular response (RVR) in patients with heart failure with reduced ejection fraction (HFrEF).

This retrospective, single-center, cohort study included adult patients with HFrEF who received intravenous (IV) metoprolol or diltiazem for AFib RVR in the emergency department (ED). The primary outcome was rate control defined as HR <100 bpm or a HR reduction ≥20% within 30 min of first dose administration. The secondary outcomes included rate control within 60 min and 120 min from first dose, need for repeat dosing, and disposition. Safety outcomes included hypotensive and bradycardic events.

Out of 552 patients, 45 patients met the inclusion criteria with 15 in the metoprolol group and 30 in the diltiazem group. Using bootstrapping method, patients treated with metoprolol were equally able to reach the primary outcome as those treated with diltiazem (BCa 95% CI: 0.14, 4.31). Hypotensive and bradycardia events remained zero in both groups.

Our study provides further evidence that short term use of diltiazem is likely as safe and effective as metoprolol in the acute management of HFrEF patients with AFib RVR and provides support for the use of non-dihydropyridine calcium channel blockers (non-DHP CCBs) in this patient population.