Bouida W, et al. - A randomized, controlled, double-blind clinical trial was conducted in three university hospital emergency departments (EDs) between August 2009 and December 2014 to determine the advantage of two different doses magnesium sulfate (MgSO₄) vs placebo in rate control of rapid atrial fibrillation (AF) managed in the ED. For this investigation, they recruited patients > 18 years with rapid AF (>120 beats/min) and randomized to 9 grams of intravenous MgSO₄ (high-dose group, n = 153), 4.5 g of intravenous MgSO₄ (low-dose group, n = 148), or serum saline infusion (placebo group, n = 149), given in addition to atrioventricular (AV) nodal blocking agents. Findings suggested that MgSO₄ seems to have a synergistic impact when combined with other AV nodal blockers resulting in improved rate control. They observed comparable effectiveness with 4.5 and 9 grams of MgSO₄. However, a dose of 9 grams was related to more side effects. Minor adverse effects were noted and significantly more frequent with high-dose MgSO₄.