Among patients with atrial fibrillation with rapid ventricular response (RVR), low-dose magnesium (4.5g over 30 minutes) was an effective adjunct to standard therapy* compared to placebo and caused far fewer side effects than high-dose magnesium.

LOw dose MAGnesium sulfate versus HIgh dose in the early management of rapid atrial fibrillation: randomised controlled double blind study. Acad Emerg Med. 2018 Jul 19. doi: 10.1111/acem.13522