Written by Thomas Davis.
Among patients with atrial fibrillation with RVR who received an initial IV loading dose, PO diltiazem was associated with better heart rate control at 4 hours compared to IV diltiazem infusion.
Why does this matter?
The debate between diltiazem and metoprolol remains unresolved. Anecdotally, many emergency physicians prefer IV diltiazem for rate control. Nonetheless, 65% of atrial fibrillation patients get admitted to the hospital. In Canada, rhythm control in the ED is a commonly used strategy to facilitate discharge. But what if a patient needs rate control? How well does PO diltiazem work? No study has ever compared PO to IV diltiazem until now.
Set it and forget it!
This was a retrospective, single-center analysis of 111 patients who received an initial loading dose of IV diltiazem for afib with RVR. 71 patients were started on an IV drip (median rate 10 mg/hr). The other 40 patients received immediate-release oral diltiazem (53% received 30 mg and 41% received 60 mg). Four hours after the IV bolus loading dose, only 27% of patients who received a PO dose had failed treatment, whereas 46% of those on IV drip failed. The retrospective design is vulnerable to indication bias as patients may have been started on a drip if they did not respond well to the initial loading dose. Nonetheless, the important take home point of this study is to remember to give something (either PO or IV) after your loading dose. If PO works, you may be able to avoid a step down or ICU admission. Better yet, you may be able to discharge the patient home altogether.
Intravenous Continuous Infusion vs. Oral Immediate-release Diltiazem for Acute Heart Rate Control. West J Emerg Med. 2018 Mar;19(2):417-422. doi: 10.5811/westjem.2017.10.33832. Epub 2018 Feb 22.
Peer reviewed by Clay Smith.