Magnesium Sulfate versus Placebo for Paroxysmal Atrial Fibrillation: A Randomized Clinical Trial

Abstract

Objectives: The objective was to investigate the efficacy of magnesium sulfate (MgSO 4 ) in decreasing the ventricular rate in emergency department (ED) patients presenting with new-onset, rapid atrial fibrillation (AF).Methods: A double-blinded, placebo-controlled randomized clinical trial was conducted in an adult university hospital. Patients aged ‡18 years with AF onset of less than 48 hours and a sustained ventricular rate of >100 beats ⁄ min were randomized to either intravenous (IV) MgSO 4 10 mmol or normal saline (NSal). Rhythm and instantaneous heart rate as measured by the monitor were recorded at baseline and every 15 minutes for 2 hours after starting the trial drug. Heart rate and rhythm were compared at 2 hours. A multilevel modeling analysis was performed to adjust for differences in baseline heart rate and any additional treatment and to examine changes in heart rate over time.Results: Twenty-four patients were randomized to MgSO 4 and 24 to NSal. Baseline heart rate was lower in the MgSO 4 group (mean ± standard deviation [±SD] = 125 ± 24 vs. 140 ± 21 beats ⁄ min]. One and 3 patients in the MgSO 4 and NSal groups, respectively, were given another antiarrhythmic or were electrically cardioverted within 2 hours after starting the trial drug. Heart rate (mean ± SD) at 2 hours in both MgSO 4 (116 ± 30 beats ⁄ min) and NSal groups (114 ± 31 beats ⁄ min) decreased below their respective baseline levels. However, the rate of heart rate decrease across time did not differ between groups (p = 0.124). The proportion of patients who converted to sinus rhythm 2 hours post-trial drug did not differ (MgSO 4 8.7% vs. NSal 25.0%, p = 0.25).Conclusions: This study was unable to demonstrate a difference between IV MgSO 4 10 mmol and saline placebo for reducing heart rate or conversion to sinus rhythm at 2 hours posttreatment in ED patients with AF of less than 48 hours duration.ACADEMIC EMERGENCY MEDICINE 2009; 16:295-300 ª

Intravenous lipid emulsion in clinical toxicology

“…Their patient was in shock that was refractory to standard resuscitation therapy but resolved with administration of intravenous lipid emulsion; no adverse events were noted and full patient recovery ensued. Other case reports relate similar hemodynamic improvement in patients with calcium channel blocker overdoses [45,46]. …”

Part 8: Advanced Life Support

“…329 Most studies showed a benefit for magnesium in rate control (LOE 1), 295,329,330 although 1 study was neutral for magnesium for rate control (LOE 1). 328 Quinidine has been shown to have greater conversion than sotalol in 2 studies (LOE 1), 331,332 although this was with greater toxicity. Clonidine has rate-controlling properties compared with placebo (LOE 1).…”

“…323,326 Sotalol has consistently been shown to be inferior in conversion compared to other drugs (LOE 1: flecainide 318 and ibutalide 308 ), but equal to amiodarone in 1 study (LOE 1). 325 Most studies showed no conversion benefit for magnesium (LOE 1), 327,328 although 1 meta-analysis showed conversion benefit (LOE 1). 329 Most studies showed a benefit for magnesium in rate control (LOE 1), 295,329,330 although 1 study was neutral for magnesium for rate control (LOE 1).…”

Magnesium for Atrial Fibrillation, Myth or Magic?

“…The Figure displays trials and meta-analyses that have randomized patients to magnesium in a range of situations, including treatment of acute AF, prevention of AF during cardiac surgery, and facilitation of electric cardioversion. [10][11][12][13][14] Although varying with respect to population and magnesium dosage, they share common features of a small sample size, short follow-up, and disappointing treatment effect.…”