Effect of magnesium sulfate on ventricular rate control in atrial fibrillation.

STUDY

OBJECTIVES

The objectives of this study were to assess the efficacy of parenteral magnesium sulfate (MgSO4), digoxin, and combined MgSO4-digoxin therapies in acutely lowering ventricular rates in patients with newly recognized atrial fibrillation.

DESIGN

A randomized, double-blinded, placebo-controlled clinical study.

SETTING

US Army tertiary care facility.

PARTICIPANTS

Fifteen adults (mean age, 62 +/- 19 years) presenting with newly recognized atrial fibrillation and rapid ventricular rate (more than 99).

INTERVENTIONS: Patients were given an initial parenteral MgSO4 bolus with continuous infusion or placebo. After 30 minutes, all patients were given 0.5 mg IV digoxin and followed for 3.5 hours.

MEASUREMENTS AND MAIN

RESULTS

Ventricular rates were obtained at baseline, every 5 minutes for the first 30 minutes, and then every 30 minutes for 3.5 hours. At 5 minutes, ventricular rates decreased 16 +/- 7% (P < .02) with MgSO4; this was comparable with rate control with digoxin (18 +/- 9%) at 4 hours. Rate control tended (26 +/- 7%) to improve with combined therapy.

CONCLUSION

Parenteral MgSO4 may be useful in the acute management of rapid ventricular rates in patients with atrial fibrillation.