Intravenous magnesium sulfate versus diltiazem in paroxysmal atrial fibrillation

Background: Drugs currently available for the acute treatment of paroxysmal atrial fibrillation have significant limitations. We assessed the safety a nd effectiveness of intravenous magnesium sulfate versus diltiazem therapy in patients with prolonged episodes of paroxysmal atrial fibrillation. Meth ods: In a prospective randomized trial, 46 symptomatic patients presenting with paroxysmal atrial fibrillation were given intravenous magnesium sulfat e (n=23) or diltiazetn (n=23) therapy. Primary outcome measures were effect s on ventricular rate control and proportion of patients restored to sinus rhythm at 6 h after initiation of treatment. Results: There were no differe nces in baseline characteristics between the two groups. Both forms of trea tment were well tolerated, with no adverse clinical events. Both drugs had similar efficacy in reducing the ventricular rate at the first hour of trea tment (P <0.05) with a tendency toward a further decrease during infusion t imes of 2 (P <0.01), 3, 4, 5 and 6 h, respectively (P <0.001). However, at the end of the 6-h treatment period, restoration of sinus rhythm was observ ed in a significantly higher proportion of patients in the magnesium group compared with the diltiazem group [13 of 23 patients, (57%), versus five of 23 patients, (22%), P=0.03]. Conclusions: Magnesium sulfate favorably affe cts rate control and seems to promote the conversion of long lasting episod es of paroxysmal atrial fibrillation to sinus rhythm, representing a safe, reliable and cost-effective alternative treatment strategy to diltiazem. (C ) 2001 Elsevier Science Ireland Ltd. All rights reserved.