ARRHYTHMIA PROPHYLAXIS AFTER CORONARY-ARTERY SURGERY - A RANDOMIZED CONTROLLED TRIAL OF INTRAVENOUS MAGNESIUM-CHLORIDE

One hundred and thirty patients undergoing elective myocardial revascu larisation were randomised to receive an intravenous infusion containi ng either 50 mmol magnesium chloride or placebo during the first 48 h following surgery. Magnesium was given to 66 patients and a placebo in fusion to 64 patients. Postoperative serum magnesium concentrations fe ll in the placebo group (from 0.83 +/- 0.06 to 0.79 +/- 0.11 mmol/1) b ut were elevated in the magnesium group (from 0.82 +/- 0.05 to 1.2 +/- 0.25 mmol/1). In total, 35 patients (26.9 %) had a supraventricular a rrhythmia, of which 11 were in the magnesium group (16.7 %) and 24 (37 .5 %) in the placebo group (P = 0.013). Three patients in the magnesiu m group had an episode of ventricular fibrillation and three patients in the placebo group had frequent ventricular ectopics. There was one death in the magnesium group associated with a perioperative myocardia l infarction. This study shows that intravenous magnesium supplements reduce the incidence of supraventricular arrhythmias following coronar y artery surgery.