The objective of this study is to evaluate the difference in response to ventricular rate control with intravenous (IV) metoprolol compared to IV diltiazem in patients taking chronic beta-blocker therapy who present to the emergency department (ED) in atrial fibrillation (AF) with rapid ventricular rate (RVR).Methods:
This was a single-center, retrospective study of adult patients taking chronic oral metoprolol. Chronic metoprolol therapy was defined as patients prescribed and taking oral metoprolol within 5 days of study inclusion. Rate control was defined as either a decrease in ventricular rate < 100 bpm or < 120 bpm if the decrease was at least 20% from the presenting heart rate.Results:
A total of 332 patients were included, with 16 patients in the IV diltiazem group and 316 patients in the IV metoprolol group. In the diltiazem arm, 68.8% of patients achieved successful rate control compared to 42.4% of patients in the metoprolol group (p = 0.067). Treatment with IV metoprolol resulted in more hospital admissions (58% vs. 6.25% with diltiazem, p < 0.001). Treatment with diltiazem was associated with a greater incidence of bradycardia compared to IV metoprolol (13% vs. 0%, p = 0.002).Conclusions:
The use of IV diltiazem was associated with a higher rate of successful response to rate control compared to IV metoprolol in patients in AF with RVR on chronic beta-blocker therapy, however the difference between groups was not statistically significant.