Abstract 13495: Efficacy of Intravenous Magnesium for Cardioversion of Atrial Fibrillation
Background: Low serum magnesium (Mg) levels are associated with an increased risk of atrial fibrillation (AF). Intracellular deficiency of Mg has been demonstrated in patients with various supraventricular arrhythmias. The role of IV Mg infusion in facilitating cardioversion of AF is not clear.
Objective: To evaluate the efficacy and safety of IV magnesium sulfate in facilitating electrical cardioversion of AF.
Methods: In a prospective, randomized, double-blind, placebo-controlled trial, we enrolled 256 patients with AF who were scheduled for electrical cardioversion. Patients were randomized to receive Mg or placebo before cardioversion using a step-up protocol with 75, 100, 150 and 200 J biphasic shocks. Patients with hypokalemia, hypermagnesemia and post-cardiac surgery AF were excluded. Patients on antiarrhythmic drugs were included as long as they were at steady state. Clinical data including AF characteristics, comorbid illnesses, treatment history, echocardiography and procedure-related data were collected. All patients were monitored for one hour after the procedure for maintenance of sinus rhythm. Primary safety end point was incidence of severe hypotension with systolic BP <90 mm Hg.
Results: A total of 256 patients (68% male, mean age 65.4±11.1 years) were randomized (130 and 126 patients receiving Mg and placebo, respectively). Baseline characteristics were similar between both groups. Average duration of AF was higher in the Mg group, but this difference was not statistically significant (112.4±20.5 days vs 87.4±10.3 days; p=0.26). There was no statistically significant difference in the success rate of cardioversion between the two groups (86.8% vs 88.6%; p=0.66), the cumulative amount of energy required for successful cardioversion (125.7±50.8 vs 129.8±51.6 J; p=0.56), or the number of shocks required to convert to sinus rhythm 2.34±1.20 vs. 2.43±1.22, p=0.59). Two patients in the Mg group spontaneously converted to sinus rhythm without cardioversion after Mg infusion. No adverse events were noted in either group.
Conclusions: In this study, which is the largest to date on the use of Mg for facilitating electrical cardioversion of AF, Mg infusion did not increase the rate of successful cardioversion of AF.
Author Disclosures: B. Rajagopalan: None. D. Narasimha: None. A. Bhatia: None. C.H. Kim: Speakers Bureau; Modest; Medtronic, Boston Scientific, St. Jude. Honoraria; Modest; Medtronic, Boston Scientific, St. Jude. Consultant/Advisory Board; Modest; Medtronic, Boston Scientific, St. Jude. D.F. Switzer: Speakers Bureau; Modest; Medtronic, St. Jude. Honoraria; Modest; Medtronic, St. Jude. Consultant/Advisory Board; Modest; Medtronic. A.B. Curtis: Honoraria; Modest; St. Jude. Honoraria; Significant; Medtronic. Consultant/Advisory Board; Modest; St. Jude, Bristol Myers Squibb, Pfizer, Janssen Pharmaceuticals, Daiichi Sankyo, Sanofi Aventis, Biosense Webster. Consultant/Advisory Board; Significant; Medtronic.
- © 2014 by American Heart Association, Inc.