Here are the conclusions, the articles seem relatively valid, although I did not take a super close look.
American Journal of Cardiology 2007 (meta-analysis): Suggests that intravenous magnesium administration is an effective and safe strategy for the acute management of rapid AF.
Annals of Emergency Medicine 2005 (randomized control trial): Magnesium sulfate, when used to supplement other standard rate-reduction therapies, enhances rate reduction and conversion to sinus rhythm in patients with rapid atrial fibrillation.
Annals of Emergency Medicine 2009 (randomized control trial): This study was unable to demonstrate a difference between IV MgSO4 10 mmol and saline placebo for reducing heart rate or conversion to sinus rhythm at 2 hours post treatment in ED patients with AF of less than 48 hours duration.
Journal of Cardiovascular Electrophysiology 2011 (randomized trial): Administration of K/Mg solution positively influences the success rate of CV in patients with persistent AF. Furthermore, significantly less energy is required to successfully restore SR and therefore K/Mg pretreatment may facilitate SR restoration in patients undergoing CV for AF.
According to Rosens’ – IV magnesium, 2-4 grams over 2 minutes, is an adjunct or third line therapy to decrease rapid ventricular response.
Time to do some reading and evaluation of the literature and make a decision if this will be used in your practice.
Rosen’s 7th ed pg 1012
Onalan O, Crystal E, Daoulah A, Lau C, Crystal A, Lashevsky I. Meta-analysis of magnesium therapy for the acute management of rapid atrial fibrillation.
Am J Cardiol. 2007 Jun 15;99(12):1726-32.
Davey MJ, Teubner D.A randomized controlled trial of magnesium sulfate, in addition to usual care, for rate control in atrial fibrillation. Ann Emerg Med. 2005 Apr;45(4):347-53.
Chu K, Evans R, Emerson G, Greenslade J, Brown A.Magnesium sulfate versus placebo for paroxysmal atrial fibrillation: a randomized clinical trial. Acad Emerg Med. 2009 Apr;16(4):295-300.
Sultan A, Steven D, Rostock T, Hoffmann B, Müllerleile K, Servatius H, Drewitz I, Lüker J, Meyer P, Salukhe T, Willems S. Intravenous Administration of Magnesium and Potassium Solution Lowers Energy Levels and Increases Success Rates Electrically Cardioverting Atrial Fibrillation. J Cardiovasc Electrophysiol. 2011 Aug 4