The influence of intravenous magnesium sulphate on the occurrence of atrial fibrillation after coronary artery by-pass operation

Eur Heart J. 1993 Feb;14(2):251-8. doi: 10.1093/eurheartj/14.2.251.

Abstract

To examine the influence of magnesium (Mg) on hypomagnesaemia and atrial fibrillation (AF) following coronary artery by-pass surgery, 140 consecutive patients were randomized to receive 70 mmol of magnesium sulphate intravenously (n = 69) or placebo (n = 71). Serum magnesium concentrations fell to 0.77 +/- 0.10 mmol.l-1 in the control group but rose to 1.09 +/- 0.17 mmol.l-1 in the Mg group (P < 0.001). The incidence of AF was 29% in the Mg group and 26% in the placebo group (NS). The AF patients were older, more of them had had prior AF episodes, their sinus rates (SR) were slower (78 +/- 10 vs 86 +/- 12 beats.min-1; P < 0.01) and serum Mg concentrations higher (0.89 +/- 0.21 vs 0.80 +/- 0.11 mmol.l-1; P < 0.05). The incidence of AF was 43% in the highest quartile of serum Mg and 23% among the rest (P = 0.056). In patients experiencing AF during the first three post-operative days, serum Mg concentrations were higher and SR slower on each day compared with non-AF patients. SR increased post-operatively less with high Mg levels (P = 0.044). In the Mg group, serum Mg and SR were the only independent predictors of AF. In conclusion, the incidence of post-operative AF is not decreased with magnesium. High Mg levels are likely to provoke AF probably by mechanisms that modify SR.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Analysis of Variance
  • Atrial Fibrillation / blood
  • Atrial Fibrillation / physiopathology
  • Atrial Fibrillation / prevention & control*
  • Coronary Artery Bypass*
  • Female
  • Heart Rate
  • Humans
  • Infusions, Intravenous
  • Magnesium / blood
  • Magnesium Sulfate / administration & dosage
  • Magnesium Sulfate / therapeutic use*
  • Male
  • Middle Aged
  • Postoperative Complications / blood
  • Postoperative Complications / physiopathology
  • Postoperative Complications / prevention & control*
  • Treatment Outcome

Substances

  • Magnesium Sulfate
  • Magnesium