The influence of intravenous magnesium sulphate on the occurrence of atrial fibrillation after coronary artery by-pass operation.
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.
Parikka
H
H
First Department of Medicine, Helsinki University Central Hospital, Finland.
Toivonen
L
L
Pellinen
T
T
Verkkala
K
K
Järvinen
A
A
Nieminen
M S
MS
D000368:Aged; D000704:Analysis of Variance; D001281:Atrial Fibrillation / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D001026:Coronary Artery Bypass; D005260:Female; D006339:Heart Rate; D006801:Humans; D007262:Infusions, Intravenous; D008274:Magnesium / Q000097:blood; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D016896:Treatment Outcome
D008278:Magnesium Sulfate; D008274:Magnesium