Magnesium Sulfate for Atrial Fibrillation Management in Chilean High-Resolution Primary Care Emergency Services: An Evidence-Based Protocol

Introduction: Atrial fibrillation (AF) represents a frequent challenge in Chilean emergency services, particularly in resource-limited settings. This study evaluated the efficacy, safety, and feasibility of magnesium sulfate (MgSO4) as a therapeutic alternative in the acute management of AF in primary emergency care services.  Methods: We conducted a systematic review following PRISMA guidelines, including studies published between 2000-2023 that evaluated the use of intravenous MgSO4 in adults with AF. Outcomes analyzed included ventricular rate control, conversion to sinus rhythm, and adverse effects. Methodological quality was assessed using standardized scales (Jadad, Cochrane, AMSTAR-2, GRADE). Additionally, implementation feasibility was analyzed considering technical, economic, organizational, and regulatory aspects in the context of Chilean SAPU/SAR services.  Results: Eighteen studies were included (11 clinical trials, 4 meta-analyses, 3 systematic reviews) with 1,237 participants. MgSO4 demonstrated significant efficacy for ventricular rate control (OR 1.96-2.49) and moderate efficacy for conversion to sinus rhythm (OR 1.60-1.75). Hoffer et al.'s meta-analysis (2022) with 815 patients confirmed significant heart rate reduction (SMD 0.34; 95% CI 0.21-0.47; p<0.001; I2=4%). The safety profile was favorable, with predominantly mild adverse effects (facial flushing 15-30%, nausea 5-10%) and low incidence of serious effects (hypotension 0-3%, bradycardia 0-2%). Feasibility analysis revealed advantages in availability, cost ($600-800 CLP/ampoule), and ease of implementation in primary emergency services.  Conclusions: Magnesium sulfate constitutes an effective, safe, and cost-efficient alternative for the initial management of atrial fibrillation in Chilean primary emergency services, especially when first-line treatments are contraindicated or unavailable. We propose an implementation protocol adapted to our local reality, with a dose of 2.5 g in slow infusion, recognizing the need for specific studies in the Chilean population.