Intravenous magnesium in the management of rapid atrial fibrillation: A systematic review and meta-analysis

Background: The aim of this meta-analysis is to investigate the effectiveness of intravenous magnesium (IV Mg²⁺) in rate and rhythm control of rapid atrial fibrillation (AF) when administered in addition to standard-of-care for non-post-operative patients. Previous meta-analyses on this topic have demonstrated the efficacy of IV Mg²⁺ in achieving rate control, but not rhythm control. Methods: Six randomized controlled trials comparing IV Mg²⁺ to placebo in the treatment of rapid AF were obtained from electronic databases totaling 745 patients. Outcomes were analyzed using a Mantel-Haenszel random-effects model and expressed as odds ratios (OR) for dichotomous outcomes with their 95% confidence intervals (CIs). Results: Our pooled analysis showed that IV Mg²⁺ given in addition to standard-of-care was superior in achieving rate control (63% vs 40%; OR 2.49, 95% CI 1.80–3.45) and rhythm conversion to sinus (21% vs. 14%, OR 1.75, 95% CI 1.08–2.84) compared to standard-of-care alone. Flushing was more frequently observed in patients receiving IV Mg²⁺ compared to placebo (9% vs. 0.4%, OR 19.79, 95% CI 4.30–91.21). Subgroup analysis showed the superiority of a lower dose of IV Mg²⁺, which we designated as 5 g or lower (24% vs 13%, OR 2.10, 95% CI 1.22–3.61) compared to the higher dose (>5 g) (16% vs 13%, OR 1.23, 95% CI 0.65–2.32) in rhythm control when compared to placebo. Conclusions: IV Mg²⁺ administered in conjunction with standard-of-care is effective for rate control and modestly effective for restoration of sinus rhythm in rapid AF without clinically significant adverse effects.