Written by Laura Murphy
IV diltiazem has higher efficacy, shorter average onset time, and lower ventricular rate for treatment of atrial fibrillation with rapid ventricular rate (AF RVR) compared to IV metoprolol, with no increase in adverse events.
Why does it matter?
The incidence of atrial fibrillation is increasing, and atrial fibrillation is the most commonly encountered arrhythmia in the emergency department. Patients presenting with AF RVR require prompt treatment in the emergency department. IV diltiazem and metoprolol are two of the most common agents used to treat this arrhythmia in the ED. We’ve covered this before, but this meta-analysis helps us take a big-picture view.
Slow down heart
IV diltiazem and metoprolol are two common agents used to treat AF RVR in the emergency department. This meta-analysis pooled results from 17 studies, involving 1,214 patients, to assess efficacy and safety of these agents.
The pooled results showed the following:
Efficacy: IV diltiazem was superior to metoprolol; RR=1.11 (95%CI 1.06 to 1.16, P<0.00001) at 30 and 60 minutes. No statistically significant difference found at 10, 90 or 120 minutes.
Time of onset: significantly shorter for IV diltiazem compared to metoprolol; weighted mean difference: -1.13 (95%CI -1.97 to 0.29, P=0.009).
Decrease in ventricular rate: IV diltiazem was superior to metoprolol for ventricular rate at 5, 10, 15, 30, 60, and 90 minutes, but no significant difference was found at 120 minutes.
Blood pressure: No statistically significant difference in systolic blood pressure between the two groups at 5, 10, or 30 minutes; IV metoprolol decreased systolic blood pressure compared to diltiazem at 15 minutes. There was no statistically significant difference in diastolic blood pressure.
Adverse events: no statistically significant difference between the two groups
So, what? This study suggests that while efficacy is similar at 120 minutes, IV diltiazem works more quickly than IV metoprolol for treatment of AF RVR in the ED.
As always, remember to use caution with rate-controlling agents in patients with secondary causes of AF RVR (e.g. ischemia, metabolic or endocrine abnormalities, pulmonary embolism, heart failure or sepsis), and be sure to treat the underlying cause.
Intravenous diltiazem versus metoprolol for atrial fibrillation with rapid ventricular rate: A meta-analysis. Am J Emerg Med 2022 Jan; 51: 248-256. Doi: 10.1016/j.ajem.2021.08.082. Epub 2021 Nov 6