Low‐dose Magnesium Sulfate Versus High Dose in the Early Management of Rapid Atrial Fibrillation: Randomized Controlled Double‐blind Study (LOMAGHI Study)
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Media type:
E-Article
Title:
Low‐dose Magnesium Sulfate Versus High Dose in the Early Management of Rapid Atrial Fibrillation: Randomized Controlled Double‐blind Study (LOMAGHI Study)
Description:
<jats:title>Abstract</jats:title><jats:sec><jats:title>Objectives</jats:title><jats:p>We aim to determine the benefit of two different doses magnesium sulfate (MgSO<jats:sub>4</jats:sub>) compared to placebo in rate control of rapid atrial fibrillation (<jats:styled-content style="fixed-case">AF</jats:styled-content>) managed in the emergency department (<jats:styled-content style="fixed-case">ED</jats:styled-content>).</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We undertook a randomized, controlled, double‐blind clinical trial in three university hospital <jats:styled-content style="fixed-case">ED</jats:styled-content>s between August 2009 and December 2014. Patients > 18 years with rapid <jats:styled-content style="fixed-case">AF</jats:styled-content> (>120 beats/min) were enrolled and randomized to 9 g of intravenous MgSO<jats:sub>4</jats:sub> (high‐dose group, <jats:italic>n</jats:italic> = 153), 4.5 g of intravenous MgSO<jats:sub>4</jats:sub> (low‐dose group, <jats:italic>n</jats:italic> = 148), or serum saline infusion (placebo group, <jats:italic>n</jats:italic> = 149), given in addition to atrioventricular (<jats:styled-content style="fixed-case">AV</jats:styled-content>) nodal blocking agents. The primary outcome was the reduction of baseline ventricular rate (<jats:styled-content style="fixed-case">VR</jats:styled-content>) to 90 beats/min or less or reduction of <jats:styled-content style="fixed-case">VR</jats:styled-content> by 20% or greater from baseline (therapeutic response). Secondary outcome included resolution time (defined as the elapsed time from start of treatment to therapeutic response), sinus rhythm conversion rate, and adverse events within the first 24 hours.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>At 4 hours, therapeutic response rate was higher in low‐ and high‐MgSO<jats:sub>4</jats:sub> groups compared to placebo group; the absolute differences were, respectively, 20.5% (risk ratio [<jats:styled-content style="fixed-case">RR</jats:styled-content>] = 2.31, 95% confidence interval [<jats:styled-content style="fixed-case">CI</jats:styled-content>] = 1.45–3.69) and +15.8% (<jats:styled-content style="fixed-case">RR</jats:styled-content> = 1.89, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> = 1.20–2.99). At 24 hours, compared to placebo group, therapeutic response difference was +14.1% (<jats:styled-content style="fixed-case">RR</jats:styled-content> = 9.74, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> = 2.87–17.05) with low‐dose MgSO<jats:sub>4</jats:sub> and +10.3% (<jats:styled-content style="fixed-case">RR</jats:styled-content> = 3.22, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> = 1.45–7.17) with high‐dose MgSO<jats:sub>4</jats:sub>. The lowest resolution time was observed in the low‐dose MgSO<jats:sub>4</jats:sub> group (5.2 ± 2 hours) compared to 6.1 ± 1.9 hours in the high‐dose MgSO<jats:sub>4</jats:sub> group and 8.4 ± 2.5 hours in the placebo group. Rhythm control rate at 24 hours was significantly higher in the low‐dose MgSO<jats:sub>4</jats:sub> group (22.9%) compared to the high‐dose MgSO<jats:sub>4</jats:sub> group (13.0%, p = 0.03) and the placebo group (10.7%). Adverse effects were minor and significantly more frequent with high‐dose MgSO<jats:sub>4</jats:sub>.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Intravenous MgSO<jats:sub>4</jats:sub> appears to have a synergistic effect when combined with other <jats:styled-content style="fixed-case">AV</jats:styled-content> nodal blockers resulting in improved rate control. Similar efficacy was observed with 4.5 and 9 g of MgSO<jats:sub>4</jats:sub> but a dose of 9 g was associated with more side effects.</jats:p></jats:sec>