Diltiazem vs. Metoprolol in the Management of Atrial Fibrillation or Flutter with Rapid Ventricular Rate in the Emergency Department

J Emerg Med. 2015 Aug;49(2):175-82. doi: 10.1016/j.jemermed.2015.01.014. Epub 2015 Apr 22.


Background: Diltiazem (calcium channel blocker) and metoprolol (beta-blocker) are both commonly used to treat atrial fibrillation/flutter (AFF) in the emergency department (ED). However, there is considerable regional variability in emergency physician practice patterns and debate among physicians as to which agent is more effective. To date, only one small prospective, randomized trial has compared the effectiveness of diltiazem and metoprolol for rate control of AFF in the ED and concluded no difference in effectiveness between the two agents.

Objective: Our aim was to compare the effectiveness of diltiazem with metoprolol for rate control of AFF in the ED.

Methods: A convenience sample of adult patients presenting with rapid atrial fibrillation or flutter was randomly assigned to receive either diltiazem or metoprolol. The study team monitored each subject's systolic and diastolic blood pressures and heart rates for 30 min.

Results: In the first 5 min, 50.0% of the diltiazem group and 10.7% of the metoprolol group reached the target heart rate (HR) of <100 beats per minute (bpm) (p < 0.005). By 30 min, 95.8% of the diltiazem group and 46.4% of the metoprolol group reached the target HR < 100 bpm (p < 0.0001). Mean decrease in HR for the diltiazem group was more rapid and substantial than that of the metoprolol group. From a safety perspective, there was no difference between the groups with respect to hypotension (systolic blood pressure < 90 mm Hg) and bradycardia (HR < 60 bpm).

Conclusions: Diltiazem was more effective in achieving rate control in ED patients with AFF and did so with no increased incidence of adverse effects.

Keywords: atrial fibrillation; atrial flutter; diltiazem; metoprolol; rate control.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Anti-Arrhythmia Agents / therapeutic use*
  • Atrial Fibrillation / drug therapy*
  • Atrial Flutter / drug therapy*
  • Blood Pressure
  • Diltiazem / therapeutic use*
  • Double-Blind Method
  • Emergency Service, Hospital
  • Female
  • Heart Rate
  • Humans
  • Male
  • Metoprolol / therapeutic use*
  • Prospective Studies
  • Sampling Studies
  • Tachycardia, Ventricular / drug therapy*


  • Anti-Arrhythmia Agents
  • Diltiazem
  • Metoprolol