Systemic Magnesium to Reduce Postoperative Arrhythmias After Coronary Artery Bypass Graft Surgery: A Meta-Analysis of Randomized Controlled Trials

ObjectiveTo evaluate the effect of systemic magnesium on the prevention of postoperative cardiac arrhythmias after coronary artery bypass graft surgery.DesignA meta-analysis.SettingRandomized controlled trials evaluating the effect of systemic magnesium on the incidence of postoperative arrhythmias.ParticipantsPatients undergoing coronary artery bypass graft surgery.InterventionsSystemic perioperative administration of magnesium sulfate.Measurements and Main ResultsTwenty studies evaluating 3,696 subjects were included. The combined effect suggested that systemic magnesium reduced the incidence of supraventricular arrhythmias compared with saline (odds ratio [OR] = 0.69; 95% confidence interval [CI], 0.53-0.90; number needed to treat [NNT] = 14). The effect was present for lower-quality studies (Jadad score ≤3; OR = 0.47; 95% CI, 0.28-0.81; NNT = 8), but it was not detected for higher-quality studies (Jadad >3; OR = 0.85; 95% CI, 0.66-1.11). There was no association between the total dose of magnesium administration and the incidence of supraventricular arrhythmias (p = 0.19). There was no effect of magnesium on the incidence of postoperative stroke, myocardial infarction, and death. In addition, magnesium did not reduce the hospital or intensive care unit lengths of stay (all p > 0.05).ConclusionsThe effect of magnesium sulfate in reducing postoperative supraventricular arrhythmias was significant when examined by lower-quality studies but not when examined by higher-quality studies. This fact probably is responsible for controversial findings reported in the literature. Also, magnesium sulfate did not reduce the incidence of complications associated with the development of postoperative cardiac arrhythmias. More effective strategies should be used to prevent complications caused by arrhythmias in this patient population.