Antiarrhythmic effect of magnesium sulfate after open heart surgery: effect of blood levels

Int J Cardiol. 2003 Jun;89(2-3):153-8. doi: 10.1016/s0167-5273(02)00449-7.


Background: Arrhythmias following cardiac surgery is still a difficult complication to treat. Magnesium sulfate is an effective antiarrhythmic agent with negligible side effects. In this study, effects of magnesium sulfate as a first line antiarrhythmic agent was compared with results of two different well-accepted antiarrhythmic agents.

Methods: One hundred patients with arrhythmia were prospectively randomized to a study and a control group. Lidocaine and amiodarone were accepted as standard antiarrhythmic agents. Patients in study group were received magnesium sulfate routinely as a first line antiarrhythmic agent. Unresponsive arrhythmias were treated with standard antiarrhythmic agents. Control group patients received only standard antiarrhythmics.

Results: Magnesium sulfate alone was effective in 56% of the study group whereas 74% of the control group were responsive to standard antiarrhythmics (P=n.s.). In study group, a subgroup analysis according to blood levels of Mg2+ revealed that magnesium sulfate was more effective in patients with low Mg2+ levels (63% for low Mg2+ levels, 55% for normal Mg2+ levels, 36% for high Mg2+ levels) and ventricular arrhythmias (60% for ventricular and 40% for supraventricular arrhythmias), without statistical significance.

Conclusions: Magnesium sulfate is an effective and safe antiarrhythmic agent for arrhythmias developed after open-heart surgery. Its antiarrhythmic effect may relate to its pharmacological properties and unrelated to normalization of the circulating magnesium concentrations. We recommend its use as a first line antiarrhythmic agent without routine measurement of blood levels.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Amiodarone / therapeutic use
  • Anti-Arrhythmia Agents / therapeutic use*
  • Arrhythmias, Cardiac / drug therapy*
  • Arrhythmias, Cardiac / etiology*
  • Cardiac Surgical Procedures / adverse effects*
  • Female
  • Humans
  • Lidocaine / therapeutic use
  • Magnesium / blood*
  • Magnesium Sulfate / therapeutic use*
  • Male
  • Middle Aged
  • Treatment Outcome


  • Anti-Arrhythmia Agents
  • Magnesium Sulfate
  • Lidocaine
  • Magnesium
  • Amiodarone